I always topped off after a certain number of runs was performed, and used the number of runs to determine how much fuel (runs) were left. Start with full fuel, do the set number of runs, top it off. Fool-proof system and you can keep track of the number of hops using the OBS dial on a typical VOR head. Start at 0 (360), 1 run is 10 degrees, 2 runs are 20 degrees, etc. There is no excuse for a fuel starvation event. You do not need fuel gages and should not depend on them. I had one freeze at a half tank one time, even bobbing a little bit. The tank was bone dry.

Glad you are ok. Be rather anal about safety in this job, always bear in mind the drop zone is about making money and YOU are about safety. They will screw you in a heartbeat and think nothing of it, seen it many times. Take care of your tickets, just say no if safety is in doubt.

Another good tip is, on a sheet of paper work out your fuel load in detail.

x gal reserve
x gals per 10k run
x gal capacity
x gal unusable
x gal per 5k run

Keep this sheet in the plane and look at it at the start of each day to remind yourself what the game plan is.