I really appreciate your testing. I don't think the maps I plan to make in the future will be anywhere near the size of the maps you have ran tests on, which is good news for me. I am curious, on the 10k x 10k map, how many provinces did you have?
but if the provinces are not sized properly I think castles and units can be too big (or maybe small) and look funny.
Solution is to use #defaultmapzoom.
Play with decimal values to tweak how the map appears in the game. You can actually create maps with large province counts on a really small image with this map command.
thanks for the tip Ballbarian. I've never had a problem per se, but have heard of it. Good to know.
Re: my huge maps... they didnt have many provinces, but because you said the province count wasnt likely to be an issue, I figured I could ignore that.