I rarely play on small worlds so a couple of questions for the experts.
Does research costs change?
Do build costs change?
Unlike C3C, a 100K Culture win still takes 100K, right?
With an 80% water world, continents & only 3 AI, it seems like there will about the normal number of turns for expansion, since both the number of competitors for the land and the amount of land have been reduced. Does that sound right?
Opening game thoughts, Spain is Commercial & Religious which means Ceremonial Burial & Alphabet are the starting techs. Commercial means more commerce from larger cities & less corruption, while Religious means cheaper temples & cathedrals and no anarchy on government changes. The Conquistador (3-2-2 @ 70 shields) replaces the Explorer and treats all terrain as roads, so essentially moves 6 tiles per turn. However it normally shows up so late, it's only effective when used in combat against obsolete units or as a pillager.
This game has a quality similar to COTM 20 where finding fresh water may be the key to success. I'm thinking about Settler SE and founding Madrid while the worker goes to the BG to mine & road. First build will be a scouting warrior and research will be at maximum for Writing then Literature for a Great Library build, then turn off the science and expand to fill up the available continent. My only dilemma is victory condition. With the right mix of opponents, I think I might try for a 20K win.