I can't find anything that solves the shield overrun issue better than your plan, Furiey, although I found an alternate version that gets the same things in a different order.
That would be to, after the first settler completes on turn 1, to immediately start another. Disband a warrior in Sogut to get the missing shield. Then build three warriors or a warrior and an archer to get to size 5.5, then start in on the warrior/settler thing.
Your plan gets settlers on turn 1, 7, 11, 15, etcetera. This version would get settlers on turns 1, 4, 11, 15, etcetera. So three turns saved on our fourth town and three turns saved on anything that fourth town builds. We would lose a tiny bit of commerce due to smaller city size and lack of an MP for a couple of turns. Military units come out the same both ways, since the extra warrior in my version would replace the one disbanded. The barb risk is slightly higher with my version, though it could probably be handled by using the MPs as escort or "lighter-uppers" at the cost of a little more commerce. If it were up to me, I'd take the risk for the earlier city, but comments are welcome.
Here is the sort of dotmap I was thinking of, although it needs tweaking.
The light-blue dot is RCP-4 from both Iznik and Sogut. Iznik itself is RCP-4 from Sogut, so that sets the maximum distance for the nearest "ring" to the forbidden palace. The pink dot near our exploring warrior is RCP-7 from Sogut; that sets the second "ring's" maximum distance.
All of the orange dots are closer to Iznik than to Sogut and RCP-3 or RCP-4 from Iznik. That means that they'll all have first-ring corruption once the forbidden palace is built. The yellow dots are all RCP-7 or less from Iznik and closer to Iznik than to Sogut -- that'll make them second-ring once the FP is built.
*Before* the FP is built, we'll have three rings. The nearest is at RCP-4 and includes Iznik, the light-blue dot and the orange dot north of the mountain goats. The orange dot by the flood-plain wheat and the one farthest east are both RCP-6, as is the yellow dot north of the barb camp. At RCP-7 are the pink dot, the yellow dot to its south, and orange dot on the hill by the spices. That makes ten cities, more than enough to build the FP.
Thoughts? Tweaks? Scrap the whole idea? I don't particularly like all the river crossing in the west, and sticking that one town on the bonus grass doesn't particularly thrill me. Moving it one tile north would put it in Inzik's second "ring" instead of the first, but it would get two bgs there instead of zero. Of course, there may be goodies under the forests, hard to say. And the jungle area is a bit haphazard.
Thoughts on using a colony to grab the spices instead of wasting a settler on a cruddy town?
In any case, I think our next town absolutely has to be by the wheat -- food is power. (Unless settler timing and worker tasks make it a lot more efficient to wait for the fourth town and settle a different one first.) The town north of the moutain goats would be my next after that.
Anyway, that's all from me for tonight. Back tomorrow.
Renata