Here is a good (I think) progression for columns or dozens. I have only elaborated it for bets bellow 100 units.
I'm sharing it because I didn't found a practical usage for it, but maybe someone here will. And I'm sorry if someone has already come up with something simillar. It is a 16 steps progression, (with max bet=80 units, bankroll needed 288 units). It can go larger, as much as you want it. It probably works a bit differently then what you are used to, but I will try to explain.
This is a progression based in groups of 2 bets (A1,A2 ; B1,B2; etc...)
In each group, if we hit the progression in the first bet, we will immediatly be in profit and finish it. If we hit the second bet of a group, we only go back one step in the progression (so if we hit twice in a row, we are guaranteed to finish the progression). If we lose on the first bet of a group, we go to the second bet. If we lose the second bet of a group, we move to the next group in the progression.
Here is the progression:
Comulative
BET Loss Win Next step
A1 2 2 6 Profit(FINISH)
A2 1 3 3 (Back to A1)
B1 2 5 6 Profit(FINISH)
B2 1 6 3 (Back to B1)
C1 4 10 12 Profit(FINISH)
C2 2 12 6 (Back to C1)
D1 7 19 21 Profit(FINISH)
D2 4 23 12 (Back to D1)
E1 14 37 42 Profit(FINISH)
E2 8 45 24 (Back to E1)
F1 24 69 72 Profit(FINISH)
F2 15 84 45 (Back to F1)
G1 44 128 132 Profit(FINISH)
G2 28 156 84 (Back to G1)
H1 80 236 240 Profit(FINISH)
H2 52 288 156 (Back to H1)
I1 ...
I2 ...
....
If anyone has questions, feel free to ask. I hope this is usefull for some system you may have. If so please share how you adapted it.
I don't think this progression will lose very often, if used with a good system. When it's lost, one can simply double or triple the betting units, until recovery of the previous progression (it will be even harder to lose a second progression of 16 steps repeatedly, I guess...
Comparing to the normal progression for columns/dozens, we can only go 12 levels down before start betting more then 100 units: