[Endoperez]

300 provinces divided between 17 nations leaves a bit less than 18 provinces per player, similar to 5-6 nations on Aran. That's pretty average, not too tight and not too sparse. 500 would give everyone 29 provinces, on average. That's like Aran with three nations.

I just mention this because in multiplayer, I don't think many would care to play a huge map. It'd be a pity if your mod/scenario didn't get played after it was completed.