Trigger: wait until a number hit twice in a doublestreet. bet the 5 unhit numbers in that ds.
progression +1/-1 (after 5 spins) -1 when hit, or flatbet....
Why not bet the DS it self?
You also cover a tripple repeat of the trigger and have a less steep progression
3 hits would be a better trigger, yes, but harder to get
+459u in 400 spins (1u bets) ...from livespins. using negative progression for 5 numbers;
1-1-1-1-1-1-1-2-2-2-3-3-4-4-5-6-7-8-9-11-13-15-17-20