I think the rachet staking plan is quite good. I generally use a percentage staking plan and adding a raceht to it can improve returns, especially as the system goes along.

Without know more indepth stats (like min, max, average, mode, mean prices ...and the number of selections and winner, etc etc) I would say that you cant go too wrong with a simple percentage system with a rachet. If it fails then the system was poor and not the staking. Hoever with those odds I would look at a smaller percentage (Eg 0.5 to 1% of your bankroll) simply because at those prices you can have a large run of outs and ruin it very quickly.