Set your Volkslogger to record every 2 or 3 seconds, depending upon
how long you expect your flight to last. This will almost immediately
make it start the "low memory" beep, so turn that off before you
takeoff. Once off tow complete your right turn all the way around
(try not to climb immediately) and you are set - you will have more
than enough resolution in your GPS trace to know exactly when you got
off tow - there is no need to notch the trace. Good luck!