For practical purposes, the $-risk per trade will be adjusted about once per month based on the new PF value. Furthermore, more frequent adjustments are allowed and desired in case of major variations in PF value and/or exchange rates.
Worst Drawdown acceptable < 25% of PF Target R > 0.25x
Target Hit rate ~0.55
Optimal R per Kelly does not yield any reasonable values for this situation, so I base my decision on R on MC analysis in Exhibit Drawdown, i.e. maxDD = 25%.
Target Risk (P95) = 0.25*PF / ~16.1R = 1.55% of PF
Chosen Risk = 1.5% of PF
The position size has to be reduced to 50% in case the PF suffers a drawdown worse than (15)% of PF value or 10R until full recovery of such drawdown.