How do you guys keep gas from spilling? 66' Dart

I got a gas filler restrctor (here) pollutioncontrol2 which helps by adding back pressure to the gas pump nozzle and acts like a newer car does, it has been on my best friensd car for over 3 years now and not one spill yet other than he didn't have the nozzle in the opening and pressed the lever (DUH moment for him, watching a girl and not the nozzle). Also a new cap repop from SlantSixDan which works awesome and I should have bought 2(1 for the wifes dart)

I have one as well, they work great. Its definitely worth installing one.