Note that LC asked me to also figure out which turn will be ideal for whipping Settler 3, which I will look into next.
Alright, so I was able to obtain the results, but analysing them isn't going to be incredibly straight-forward.
The PPP currently has the Galley taking the "round-about route" in order to pick up the Worker and drop it off by the NE + E + E PFor (aka the Gold Forest). If we use an economy of movement with the Galley, we can actually delay Settler 3 by up to 2 turns.
So, we can whip Settler 3 on any of Turns 80, 81, or 82.
Each turn of delay, on the surface, gives us an extra 17 overflow Hammers. But it's unfortunately not that simple.
Each turn of delay also means that we will settle Marble City a turn later. Therefore, we will get 3 less base Hammers in the Lighthouse, which translates to 3 less base Hammers that will get overflowed into The Oracle at a later date.
In addition, we pay 2 more Gold in Maintenance per turn upon settling Marble City, but we gain 3 Commerce (one for the City centre plus 2 for the Trade Route)... and the Trade Route "counts" even on the turn that the City is settled.
But then you have to factor in some other interesting results: when Paris is at Size 6 at the same time that Marble City exists (and with Gold City remaining at Size 2 for this time period), we pay 1 extra Gold in Maintenance.
Then there's the fact that by whipping on Turn 82, we will actually complete our Monument before starting on Settler 4, which means that when we are at City Size 6, our 6th population point can work a Coast for +2 Commerce (the Hammers invested into the Settler will remain the same, due to the way that you get "credited" for Unhappy people's Food while building a Setter and due to the fact that working the Coast is "Food neutral," meaning that our Food getting converted into Hammers is essentially "Hammer neutral") or we could work a Cottage (come on, you know that you want to!
) for +1 Commerce and +1 turn of Cottage growth.
However, it won't be long for our Unhappiness wears off, but there is a tiny bit of gain Commerce-wise by getting that Monument earlier.
Then, we need to throw in the fact that delaying the Settler simply puts more Hammers into the Monument sooner.
It looks like, after building Settler 4, we are trying to overflow some Hammers into Worker 2. Well, assuming that we whip Settler 4 at the same time in each Scenario (where the three Scenarios are essentially "Whip on Turn 80," "Whip on Turn 81," and "Whip on Turn 82"), then what we've done is moved the overflow Hammers from Worker 2 and put them into our Monument.
So, essentially, Worker 2 will come out slower (I haven't tested how much slower, but it's probably at least 1 turn slower and possibly 2 turns slower by whipping on Turn 82).
Now, what I did not test, and what we should probably do, is that if we plan to whip on either Turn 80 or Turn 81, meaning that we won't complete the Monument before we complete Settler 4, then we should probably start building Settler 4 when we're still at City Size 5 (say, 1 turn before growing), so that we don't lose that 1 Gold per turn of Maintenance when Paris grows to an unhappy Size 6.
As I said above, if we were to whip on Turn 82, then we'd have the Monument, so growing to Size 6 before starting on Settler 4, in that case, would let us work a Coast or a Cottage, since the Monument would erase the Unhappiness.
Now, it should be noted that without the Monument, we will lose 1 Whipping Unhappiness on Turn 90. Okay, we'll lose that Whipping Unhappiness if we have the Monument, too, but having the Monument makes us have 7 Happiness... which, of course, introduces another wrinkle: should we consider the possibility of growing to Size 7? I'm going to tend to say "no, probably not," since we only have 1 more Coast square to work instead of, say, another Mine, and then you have to factor in the fact that growing to Size 7 costs more Food than growing to a smaller City Size would. But the point really is that in all 3 Scenarios, we'll be able to work 6 squares at City Size 6 on Turn 90.
Okay, so here are some numbers on Turn 90. Turn 90 is a good comparison point because all 3 Scenarios will have 6 Happy people on this turn, so the "Turn 82 whip" scenario will stop "gaining" extra Commerce on this turn.
Turn 90 numbers:
A) Turn 80 whip: 24 F, 71 H (51 H in Settler 4, 20 H in the Monument), 0 extra Gold*, 21 base Hammers in Marble City's Lighthouse
B) Turn 81 whip: 24 F, 71 H (34 H in Settler 4, 37 H in the Monument), 0 extra Gold, 18 base Hammers in Marble City's Lighthouse
C) Turn 82 whip: 24 F, 71 H (17 H in Settler 4, 45 H in the Monument--i.e. it is built, 9 H in another Work Boat (or it could be put into a Warrior or a Galley or whatever), 2 extra Gold, 15 base Hammers in Marble City's Lighthouse
* Note that I set the Science Slider to 0% to avoid having bonus Flasks potentially messing up the comparison. So, I'm just comparing the relative values of Gold obtained, which represents the combination of Maintenance plus Commerce.
What's really neat is that when I took a snapshot of the numbers on previous turns, such as on Turn 85, "Turn 82 whip" was 1 extra Gold BEHIND "Turn 81 whip," and was 2 extra gold BEHIND "Turn 80 whip," but then later caught up and passed them both.
The catching-up part is due to Paris being larger (Size 6) when Marble City did not exist and Paris being smaller (Size 5 or smaller) when Marble City did exist. The extra bit comes from that 1 additional turn of Happiness at City Size 6 due to having the Monument early.
Okay, so on paper, Scenario C) looks good, in that we get the most total inputs (2 extra Gold).
However, we also have placed our Hammers in a Monument and 9 Hammers in a Work Boat/Warrior/Galley instead of in Worker 2. That early Monument is essentially only worth 2 Commerce.
I'm not quite sure what's happening on Turn 90 and afterwards, but it looks like we're staying at City Size 6 for a while while we manually build Settler 4 and/or Worker 2. I'm not sure why we'd still build Settler 4 on Turn 90, as the PPP suggests, because doing so means that instead of having Settler 4 be a 3-pop-whip with near-maximum overflow Hammers, we turn it into a 2-pop-whip with very few overflow Hammers.
What it comes down to, though, is that settling Marble City sooner does a few things for us:
a) Gets us more Hammers in Marble City's Lighthouse, which means more Hammers in The Oracle, which possibly translates into an earlier Oracle date (say, just guessing here, 1 turn saved on The Oracle for every 2 turns of Marble City existing)
AND
b) Gets us more Commerce. Now, yes, the numbers above have Scenario C) "catching up" and then "coming out ahead." However, if I played a bit more smartly (now that I know about the whole "grow Paris to City Size 6 and pay +1 Gold of Maintenance" issue), I could have spent more time at City Size 5 while building Settler 4 and saved, feasibly, 1 Gold per turn. That savings for 2 turns for the "Turn 80 whip" scenario would then equal the 2 Commerce that we gain by having the earlier Monument in the "Turn 82 whip" scenario. So, essentially, I think that I'll be able to match "Turn 82 whip"'s Commerce with a slightly smarter "Turn 80 whip" approach
AND
c) Allows us to store more Hammers into Settler 4, which would overflow into the build item that we want the Hammers to go into (Worker 2), getting us a faster Worker 2 instead of a faster Monument plus partial Work Boat/Warrior/Galley
So, I think that a "Turn 80 whip" approach will be best, even if it does fall behind by 2 Commerce, while I think that I should even be able to save that 2 Commerce so that it won't fall behind at all (I'll have to try and test for that possibility next).
Now, what's even more interesting is that we will have 20 Hammers invested into a Monument with the "Turn 80 whip" scenario (not quite enough for a 22 H Warrior) but will have 37 H with the "Turn 81 whip" scenario. So, is it worth delaying Worker 2 for what will probably be a 1-turn-delay in order to get out another Warrior?
The answer is probably "no, we don't need that Warrior so soon." But, we could go with a "Turn 80 whip" approach and then, after completing the Monument, sneak in a Warrior before the Work Boat, if doing so will help out Gold City more than getting a faster Work Boat would help any City. If I am not mistaken, the PPP has us starting on a Work Boat with 0 Hammers invested into it on Turn 97 and only has us completing this Work Boat later... so, there might be a chance to fit in a Warrior instead. Anyway, I'm not sure if we really need a Warrior, but since I highly doubt that we will need that Warrior immediately, I'm going to push for the "Turn 80 whip" scenario.
Okay, since I can do so, I will just do the testing of the "Turn 80 whip" scenario where we delay growth to Size 6. Hmmm, it looks like there are actually THREE turns where I can save 1 Gold of Maintenance, so we end up saving even more Gold than Scenario C). I'll call this scenario "Scenaio D)":
D) Turn 80 whip -> Turn 86 build Settler 4 -> Turn 89 build the Monument (so that we can grow to City Size 6 in 1 turn): 24 F, 71 H (51 H in Settler 4, 20 H in the Monument), 3 extra Gold, 21 base Hammers in Marble City's Lighthouse
Okay, yes, I was right: we have a clear winner here with Scenario D). It's a bit more micro-management intensive, but that's one of LC's specialties, so I trust him to be able to execute this minor gain in efficiency.
later, maximizing food in granary, and working the gold tile. 
icon.
You won't REALLY quit the team if we get beaten to The Oracle, will you? 
to 2
. Nice of you to crunch the number though.
