I've looked into this extensively in the past, and for one reason or another avoided it - MOSTLY because I simply don't have near enough volume to be able to offer competitive rates with the big guys. It can also be a bookkeeping nightmare, depending on the site you are dealin with.
What I've finally decided on is partnering with one of the big sites. I've had extensive conversations with them, and I think what we've worked out is going to be a great deal. They offer the BEST rates on the market (27% for Full Tilt, for example) and they have plenty of happy customers. As an affiliate of THEIRS, I will simply refer you guys to them, which will in turn get me a (very small - like 3%) piece of the rake back YOU earn. And yes, that's 3% of what YOU get, not 3% of your total rake. In other words, if you generate $1000 in Rake at Full Tilt in a month, they will pay you $270 and I'll get $8. Yes, 8 bucks. But still, every little bit helps, and this is the best deal for YOU GUYS.
Alternatively, I could try to mirror their program to earn more money for myself, but instead of offering you 27% to start, I'd only be able to offer a maximum 20% or so until I established a big program with lots of players generating lots of rake, and it would have to be less than that if I actually wanted to make any money. So that's why I've decided to go the other route.
This is all but set up now, so I'll have a link for you guys by the end of the week, for sure.
As for question #1.... I wish I knew, because I'm in the exact same boat as you. What I'd love is if you'd be a guinea pig and figure out the answer for the rest of us.
P.S. What the hell is "rack" back?