If you want this game to be an enormous hit, you will need to have a couple of things done in steam.
1) Have the beta updates put into the steam newsfeed, this will attract a lot of attention form people that will look to see what this game is about.
2) Have a Sins Rebellion forum section in the Steam forums. Though this will up the task of looking through posts, a lot of steam users are too lazy to post on other forums and so you will be able to get a greater amount of feedback for the game.
3) Lastly (and I know you do not like taking payments before the game is released), you should have the game on pre-order in steam with promise of being allowed into the beta on perchance. This will get you a tonne of money as steam is the best platform for launching a game on at the moment.
I hope this is useful,