Also, why are you sticking with Ethereum only? There are plenty of other cryptocurrencies out there, how about branching out into something unique such as ADA or TROn gambling?
I'm not really sure if autobet system is a must feuture on a roulette game because I do not see how fun to play roulette automatically as there are many options to bet on roulette unlike dice which is only about over and under bet. I myself do not really like to play roulette, but if I have a chance to play roulette then I will play randomly by choosing numbers/row and most likely will change the numbers/row in every few bets or even in every bet. So it will be a bit hard to make autobet in roulette game IMO.
Yes there is so many possibility to bet on roulette but I think if there is someone who bet only between red and black then it should be possible to implement autobet system on their site. The multiplier is 2x so it will be like a normal dice site. But if OP are trying to implement autobet then he should get so many possibilities outcome "if conditions"