Nitrous plumbing A1A...??..

One thing I’ve learned playing with start retards over the years is to find out how much you have to retard to get it to not kick back, add 2 degrees more and you’re golden.

I’ve seen guys pull too much out and they start really hard when hot with too much retard. They crank more than I like.
It's likely that I will never use the start retard part but mainly just the timing retard triggered by the nitrous relay trigger. I'll put it in line behind my hand trigger on the shifter grip but before the full throttle trigger. That way when I want to test it I can just have my wife hit the trigger while I have my timing light on it...