Tom here's a safe adaptation for playing with a 1 unit start for those who can't bet fractions of a unit and can't afford to start with 4 units.
1a) 1-1 If L -2 go to 1a
If W +1 go to 1b
1b) 1-1 If L -1 go to 1a
If W +2 go to 2a
2a) 1-1 If L 0 go to 2b
If W +3 go to 3a
2b) 1-1 If W +1 go to 1b
If L -2 go to 1a
3a) 1-1 If L +1 go to 3b
If W +4 go to 1a
3b) 1-1 If L -1 go to 1a
If W +2 go to 1a
WW/W/W +4
WW/W/LW +3
WW/LW/W +2
WW/LW/LW 0
WW/L/L -2
WW/LW/LL -3
WW/W/LL -1
L -2
WL -1
GLC
One thing I forgot to mention is that you can play this flat bet. If you do every thing above is meaningless. Or you can play it with a progression. For the progression, if you reach -6 you should increase your base bet to 2 units. That means you will double every bet. If you reach -18 you should triple your base bet meaning you triple all the other bet sizes.
Here's the chart:
-5 or above start with 1-1 unit
-6 to -17 start attack with 2-2 units (double all bet sizes)
-18 to -35 start attack with 3-3 units (triple all bet sizes)
It's up to you how far you want to go with the progression.
GLC