If you can find 3 or 4 numbers that will not come out on the next spin, then you have found the Roulette Holy Grail.
I have many Recouping Systems, they require different amounts of chips, and have different win to loss ratios, there risks are different, some have 9 numbers that can make you lose others have 3, there are different profits from 2 to 6 chips, but it all comes down to this.
"Can you find 3 or 4 numbers that have a very small chance of coming out on the next spin" and can you pick them, enough times to over come the win loss ratio.
If you can, then you now can bet, recoup the bet amount, bet, recoup the bet amount and when you get the win all the win is yours.
Even if you can't beat the win loss ratio if you can finance a bet that wins a good amount of times or a lot of small wins, then you are a winner.
I am going to do tests on a the 30 chip Recouper that wins 6 chips profit only if that dozen wins.