I'd suggest keeping odds of winning in your advertising, similar to odds provided by the lottery. You don't have to promise the return percentage (except the max) but letting people know there's a realistic chance of winning will earn you business...seriously.

I would play, but 190% return is scary. That's not safe for gamblers, because of how highly unsustainable it is. Try 120-130% this is a much more sustainable and allows you to last longer.