this whole thing just reeks of wrong to me. Not provably fair, nothing too tiny about those pay-in's either. I've got to say I think this needs to go back to the drawing board, I'd be inclined to dial down both the buy in and pay outs. I think you're going for a 'fun-time-bit-of-a-flutter' type users here not pitching yourself up against those more serious 'seals with clubs' types.
just my two satoshi here