Map Size - Memory Restrictions

Quick question... I am in the process of getting a new computer so this will not be an issue for me for long but until then...

I have 4GB of ram and throughout alpha and beta I was able to play on large maps (and sometimes huge). Once the game was released the devs restricted the ability to choose large maps if you didn't have enough memory. (I personally didn't mind the small delay between turns later in the game).

So when I load up the game the options are preset to a Small Map Size and I can enter the game and play on a small map. However, if I go to select another map size it only says I can play a Tiny Map Size in the menu. In fact, if I click tiny and then try to reselect small again it will not let me select and play small at all. It is grayed out and I have to exit the screen and come back in to get small back again.

Now here is my question. I know the game remembers the game options from the last created game. Is there a way to go into a file and change the 'remembered' map size from Small to Large? I tried finding the options file but couldn't see it anywhere. I want to change it so it is set to large when I enter the game options screen. If this doesn't work does anyone know a way to force the game to play on a larger map?