I will try to make the argument on why it's wrong to rush a settler from size 1. It is surprisingly difficult to put into words because there are a lot of different moving parts, so, please, bear with me.
To start with, I will recap some of the reasons that have been raised for such a build.
Soundjata says that it takes a long time to grow Ulundi, and this is right. In fact, it takes 7 turns to grow to 2 and then 5 turns to grow to 3.
However, it would also take a long time to grow a different capital and this is because the food specials take time to improve. Growing to 2 on wet corn or even pigs would still take 6 turns, then most capitals would grow to 3 in 4 turns. Some of the very best cities would grow to 3 in a mere 3 turns.
So, Ulundi : not the best growth but we're only looking at a 1 turn delay towards each size compared with very standard capitals.
I think it's important to consider what size 3 Ulundi looks like :
6 happy cap, +7F, +5H per turn. This is a very capable city, an efficient pump that still has a lot of potential for growth.
Now, Sampsa says that rushing a new city is good because it immediately contributes yields. Here we're looking at +3F+2H at size 1, very nice.
First, I'll point out that the commerce comparison can be skewed (it sure is nice to have trade routes, though), because Ulundi can also grow on commerce tiles and those do not require 100H to work, nor do they incur maintenance hits. This is not the main point, though.
I believe it isn't appropriate to look at the new city yield from the Demographics point of view. How have I improved my demographics ? +3F+2H.
To me, the question is rather : when will this new city have contributed a relevant item ? And by that I mean a worker or a settler.
It's all good to have +2H but it doesn't mean a damn thing until the item in production has been completed. I think this is very important.
And that brings us back to the Soundjata point where : city 2 will also need time to develop (6 turns to grow in the case of a corn ; 8, here, since we're looking at an already farmed floodplains) before it is capable of contributing an actual, factual item.
So, wer'e looking at a time frame whereboth of those cities are size 1, we have 1 worker, 1 improved pasture, a farm and we are closing in on Bronze Working (due circaT30).
The risk, here, very real, is that we are not ready to take advantage of Bronze because we have not set up a proper pump city yet. Alternatively, we could still try to push production from size 1 cities (chopping more workers and settlers) and never actually set up our commerce base.
Now, let's look a little more closely at how Settler at size 1 works, because it will help make the comparison with size 3 Ulundi.
The worker improves the cows (5T) and then the eastern floodplains (9T). The settler takes 14T to complete and we can plant city 2 after 2 travel turns.
So : city 2 is settled on T27 (remember, Bronze due circa T30). On that same T27 : settler is out T25, so Ulundi has 2 more turns of doing stuff. Worker also has 3 more turns of doing stuff after completing the farm.
This is our situation and we are not close to completing another item.
If we go back to Ulundi size 3 : Ulundi hits size 3 after 12 turns of growth. That would be T23.
And it takes it 8 turns to build a settler. Put otherwise, this is a 6 turns delay towards city 2compared with settler at size 1. Settler out on T31.
At this point, Bronze is done or looming and we can use the very capable size 3 Ulundi that I describedat the beginning of this post. +7F, +5H.
Ulundi can build a worker in 5T, evenwithout a chop. With double chops, it can build a settler in 5T. We have a lot of forests and want to clear riverside to cottage. A very capable city.
Now, remember our 2 miserable cities from T27 ? What are they set up to do 4 turns later ?
None of them has reached size 2, they're kind of halfway there. Maybe one has started on a second worker ?
Let's say we task Ulundi to go settler, worker to make use of the cows and prepare for Bronze. After having stagnated for 14 turns on a settler, it can now keep stagnating foranother 7 turns to provide another worker. It will now have stagnated a grand total of 21 turns to produce a whopping 2 items !
So, this is the miserable timeframe where none of our cities are properly equipped to do anything, or complete any item, or keep up with the requisites of our tech discoveries.
If we have Bronze, we want to be able to chop.
Establishing a capable city, that is in measure to complete items in a good timeframe is and should be the first priority.
Population growth is the ultimate goal and that can only be achieved by reducing stagnation times.
I hope this wasn't too much of a bother to read and addressed relevant points in a relatively convincing and organized manner. Again, this is not an easy task to make this argument.
For reference, because the timings on Bronze and city 2 are so close, I do believe there's a good chance size 3 Ulundi wants to chop its second worker before one is sent over to improve the food in city 2.
Also for reference, I can see the strategic use of an Eastern city. There are ways where Sury's culture becomes oppressive and it could be a good idea to use the 3 tiles buffer between cities to limit his options.
I wouldn't rush over there, however, and claiming 0 resources with city 2 is a big no-no for me. If it's only to work shared tiles with the capital, Ulundi can grow. I'd rather concede the whole area to Sury and settle a perfectly fine 5 yield tile outside of the capital's BFC.
Finally, for reference, I am perfectly fine with a couple of farmed floodplains. With 6 happy cap to start with, I welcome the +7 food surplus (or even +8 with the other floodplains). There are plenty of other tiles that can be cottaged and grown upon. I will concede that farming floodplains is not the ideal investment for early worker turns but it isn't like we have better food at our disposal and it is very important to secure the food surplus.