What i took from the 100+ page grassroots thread about double dozen betting was that in 3 spins you win the first 2 bets a lot. Like only once in 25-30 spins you actually get into the situation where you loose 3 bets in a row (using the grassroots "patternbreaker" kinda system where you bet against a unique pattern like 123, 312, 213 etc. Conclusion: so why bet a third expensive time if you loose the previous 2 bets? instead just keep betting 1, 3 continually & should you loose the 2 previous, that wait for a virtual bet. If you havnt the patience for the 1, 3 grind, then instead do 1,3 then 2, 6, then 3,9 and revert back one step once in profit and/or win. One way or the other double dozen will always feel very 3 step forward and then 2 backwards again & again.

With a win chance higher than 50% statistics also suggest that you should reverse your betting. Aka bet 3, 1 instead of 1,3. Again taking the grassroots stats, like in 30 spins (10 sets of 3) you win like on first bet in 5-6 sets, you win on 3-4 sets on second bet and 1 one set you get to 3rd bet (win/loss). Of cause its grindy too and you can argue doing 3, 2 or just flatbetting or ladder again.