Suggestions on how to play Pax Romana using PBeM

I have Pax Romana but have never played anything other than the two player scenarios. I’m intereted in playing the advanced game with 4 players, but only with PBeM (not enough large chunks of time to make it worthwhile). However, because of the game mechanics it’s not really condusive to PBeM, unless you want to be emailing all the time for small things (i.e. Do you want to play a card?"

Anyone play Pax Romana by PBeM and have good suggestions?