Hi Martin,
I don’t know enough on this one to tell you which is best or if the deal is fair. Feel free to call me or PM me and we can go through it if you would like.
Regarding your case (based on what is posted here), I don’t think you should loose any legitimate players regardless. I would also require Rewards to proved proof on the fraudulent Russian bonus abuser, and ask for confirmation that this player has been banned from all their casinos.
Regarding commission models it should be up to you which one you select, and the preference is yours.
The Wager Share model is 35% of the players wagering with no admin or royalties from your commission. The tiered RevShare Model maxes out at 35% of the net loss.
I hope this helps.
Brooke