To spray or not to spray

I used a plate system on my '67 A body 440 race car. It was a 10.58 car on motor, 9.90 on spray. Never had any nitrous related problems.
I also had a plate system on a '55 F-100 with a Chevy 355 small block. It was a blast on the street. There were no nitrous problems with it either, but I did have full open throttle position switch and an RPM switch wired in series so the spray could not energize if the carb secondaries were not wide open and the RPM was not at least 2000.