One twist I have learned with pbem is to do joint hosting. It speeds up play, but mostly the benefit is both players host every other turn as then you get to see every other turn run.
To do this, one player starts the game and plays the first turn. Saves and sends all files.
Then the next player makes the moves and executes the turn. Then, make the next move, saves and sends files.
From then on, each player makes a move, executes the turn and make a new move.
I think it is much better than a single host for two and three player games. With four or more, a single host works best.