Recommendations on what settings to use are really hard to say. It really depends on your play style and preferences. I would suggest starting on a Standard sized map, Custom Continents (and if you want, select 4 continents). Also try normal speed, and increase the difficulty off of chieftain (again, base it off of how difficult you want the game to be), but I would suggest that, if you're coming from vanilla BtS, go down a difficulty or two, since you have to relearn much of the game.
After this 'test game', decide if you would like the game to be more prolonged (which, among a few other things, allows for military to not go obsolete as fast), if you would like a bigger map (if you computer can handle it), and if the difficulty was decent, or if the game was too easy (I wouldn't suggest increasing difficulty by more than 2 steps).
As for me, I play on Giant, RoM_Custom_Continents, 5 continent, Marathon, with the default (large) number of civs. I turn off time, cultural, and space victory. Lately I've been trying a strategy as Huayna Capec of the French, although I tend to switch leaders and civs every game or two. I tend to switch the difficulty between emperor and immortal, depending on if I'm trying a new strategy or not.
I hope this helps you decide!