You'll actually find there are more scammers in mainstream than in adult.
As far as the percentage splits go with mainstream publishers, you can actually get away with as low as 20% up-to 75% and they'll be happy (for the most part) so long as your product sells, they also don't seem to put as much weight on things like traffic leaks to social sites, publisher program links, etc...
http://www.ecsuite.com - CCBill's mainstream processing arm, you might also want to go with a company such as ClickBank (because they have a HUGE market presence) the only downside with ClickBank is what they charge to get a product in their network, $50 a pop.
Mainstream is a lot more profitable than adult, even today, you just have to take your time, establish yourself as an authority on the mainstream networking platforms and socialize, socialize, socialize...