I think the analysis shows that we should only vassalise one of the current civs (say Mansa) and then when we attack the next (say Churchill) if he offers to vassalise to us we simply refuse. Then if he vassalises to Bismark who cares? We just continue the war with us and Mansa against Bismark and his vassal. I don't see a big problem except a potential delay. This technique of prolonging the various wars allows us to gain a larger % of the land for ourselves where it counts at full value rather than only half value if it is held by vassals.
We really need to know about the missing civ(s) and the size of ithe landmass they have. That will allow a definite plan of domination.
Domination is easily possible, the question is, how quickly can we get Sisiutil to pull it off?
the more i think about this the more i like it. yeah if we make assumptions about getting
all the land tiles on this continent it sounds super easy. but really, we have no way of encouraging them to settle every junk tile to get somebody's culture on each tile of the continent. yes they always have a settler around somewhere, even in 2045 AD, and they'll always expand, but, will they do it at the rate that we want? including number of cities, cities spread far enough apart, and spreading out culture from those cities so that tiles between fat crosses are counted too? oh the waits i've had when i've been on purpose running that culture slider trying to get that last two percent to hit the magic number!! churchill and/or bismarck, no matter how big or small, as a vassal certainly won't help that any, only make it harder, since our push at the end would by definition have an effect on less total area. only exception is if he/they have their entire territory (1) the right size to put us over at 50% but not too big so that only 50% puts us under and (2) completely covered in their culture without annoying gaps.
bright side: if they're vassals, you automatically get open borders with them (you have to grant them OB with you tho, that side isn't automatic). so if they did have a gap in their territory you could go settle it.
you're getting at what i was wondering about the formula. i really don't know that we know enough about the map to assume that our continent is big enough that if a fairly significant portion of it counts only 50% for us, as vassal territory, rather than 100% as our own, that it'll be enough.
Really? It only tells that we need to get over a certain % of landmass before vassalizing the last one

. Let's say you see 55%, and Bismarck has 20%, it means that if you vassalize him, you win!
If Sisiutil vassalizes Mansa Musa and they both go for churchill, no city should be razed (not counting MM's crappy cities). After that, it's time for settlers and more units to get bismarck. Keep taking cities (he cannot vassalize to any one else

) while pushing the culture slider to swallow has many tiles as possible, (or use artists running castes system) until you see the magic number making your land % + half of bismarck's land over the limit.
Yep, there is hardly any challenge left in this game.
go Sisiutil, go
it's entirely possible that i'm misinterpreting what you're saying (i'm reading during lunch, and typing with my mouth full, how rude)--seems to me "we'll do a lot of the work but we'll also sit back and let them do quite a bit for us too"? i'm just not so sure that'll work out the way we want it to. you want to go to war with mansa now/soon and make him a vassal and a friend again afterwards. then we settle a lot, while watching F8. meantime as efforts allow we go search for mystery-civ i figure huh? then when F8 looks good, bang on bismarck? oh i don't see the churchill ending there, we demolish him and settle his former territory before the F8/bismarck step?
one other thought: will watching the F8 give us an accurate count? i've had situations with 4 AI civs still alive, 3 are my vassals. the victory screen showed 4 rivals left, since in theory they could become free again. however i did vassalize the 4th and the game ended in a conquest victory that turn. this makes me not sure at all that the % of land area will show the right way. say we make mansa a vassal soon, going by my experience above i think his territory would not show on our F8 screen (under the theory that he may become free again someday). so we'd actually be a little bit higher than we could see. not a huge deal, just a random thought.