agree but sometimes there are cases when fearless ones (not because they conquer their fear (or have an effective method), but because they do not have a clue about real danger and walk into it and walk out of it unharmed) can get surprising consistent positive results for a while... but to get the consistency with trembling knees that is really miraculous
answering the original question. its simple really. use pnl as ticks per contract (or other fixed size).. so whatever size you trade you'd see same ballpark of figures in the pnl.. while you are trading.. obviously you need to finish your day with real numbers but not before you close the trading screen.
that is when I am alert and do not expect account to go. My losses are mainly caused by lesser signals, generated when not motivated enough.
Certainly---and risking 25% of account on first trade, 33.33% of account on second trade and 50% of account on third trade is a great strategy especially with lesser, un-motivational signals.
thats what works for me. We all have to expose our strong sides whenever possible and minimise exposure of weak points. not quick process, i may add, figuring it out.