It may be worth checking in with the people who did the Space Empires 4 play by web site. It was a very effective and user friendly site and I believe the mechanics are quite similar to Dom. It was community produced and funded, with the blessing of the developer and Shrapnel. It might be possible to piggy back some of their ideas and experience. I just checked and it is still running, several years since I last used it, so it is doing well.
http://seiv.pbw.cc/text/index.jsp