For reference, what was the max number of tiles on civ3 and civ4 ?
In Civ3, it's 65,536 tiles. However, there also is a 512 city limit, which limits you to about 30,000 tiles if all will eventually be occupied by a city; if you have lots of water or make some terrain like tundra or desert non-settleable, it's higher (although it does get slow with 350+ cities).
In Civ4, I don't think there's a hard limit, but memory usage provides a soft limit. In practice, the limit tends to be somewhat smaller than Civ3, since if you push it too much you get memory allocation failure crashes, which are unfortunately very good at making things less fun.
230x115 would be 26,450 tiles, or slightly less than the Civ3 de facto max without making some terrain unsettleable. But that isn't necessarily materially less. Turn times, city sizes, etc. will all make a difference. I see you're already off to a great start with the YnAMP - it looks great from the screen shots, and even if that's the 180x94 size (16,920 tiles), that's about what you could achieve in III and IV before you got significant AI slowdowns (III) or a risk of crashes (IV).
Big maps are definitely something I'm looking forward to. I never got very much into V in part because the number of cities and map size tended to be lower than previous iterations. If there wind up being mods with lots of cities on big maps without super-slow AI turn times, that would be a significant draw in getting me to pick up VI sooner.