Phil,
I won't attempt to "write" how I wind the drum, but will say it includes taking up some movement and then shifting my grip and drum orientation so that I can use my right hand and thumb to have better control, and then press down the latch to hold the arm in its catch- then IMMEDIATELY close the extended arm of the lever. That way if something goes south that "scythe" is not waiting to break your fingers.
I worry not so much about the winding, but the off chance that the locking button may fail!
I'm not sure I could wind the drum if I were left handed though.
