Sooner or later someone will make a tool. You enter your opponent's address, point to the file, and it will split and send it in several emails. Doing this manually in your email client is just cumbersome.
It's not a question of optimization. The game is not really designed for pbem. The big question was if we wanted the feature even with huge files. We said yes of course.
Yeah, MGK, apparently it does grow. The biggest I have heard mentioned is 30 meg. Obviously it depends on the size of the scenario. When you think that each turn replay has to instruct the receiving computer on the trajectory of every bullet fired, you can see why. Having said that, I'm sure in time they could get it down because even setups are big, and surely they don't have to be.
See the picture for Star Trek Borg spoting
My opponent can see my forces but cant shoot at them - I can't see his forces (USA - stealth units) but we both are moving from the same setup zone !!