I would suggest looking at geo targeting, I haven’t implemented anything like this though, but it has been on my mind to do so, to increase conversions and have more control over traffic.
Sending US traffic to US casinos, and sending non US traffic to other casinos.
Might be worthwhile checking with some of the affiliates manager what their average player value is also at their casinos.
Also.. I really do believe that one webmaster may do well with seo traffic at a particular casino, and another webmaster won’t.. shop around till u find the right one?
Hit me on skype, and we can do some brainstorming!