I have read that you cannot apply Porrondo to roulette. What if you Bet $2 on Black for the first 2 spins. Then for the next spin, if you can divide your BR by 3 then put $1 on a split and $1 on a different split (to cover 4 numbers, roughly 10%) or if you cannot divide your BR by 3 then put $1 on Red and $1 on Column B (to cover roughly 75%)?
Or, what about:
Bet 1 = $6 on Black
Bet 2 = $6 on Black
Bet 3 = If can divide BR by 3 then to get 10% put $3 on 3-6 split and $3 on 33-36 split
or
If you cannot divide BR by 3 then to get 75% put $1 on 1st dozen, $1 on 3rd dozen, $1 on 14, $1 on 17, $1 on 20 and $1 on 23?