Nitrous plumbing A1A...??..

I have had every liquid fuel pressure gauge take a crap, one I stored the car in an un-heated garage for the winter, the gauge would read, and appear correct, but actually was reading 3 psi high.
I will never buy another one, just use plain Autometer fuel pressure gauge and be done with it.
I was pretty sure what Pittsburgh was alluding to LOL was that under temperature the gauges do fluctuate in their readings. Really my fuel system that I made is very standalone and can be ran without the engine on. I plan to circulate it and get a good pressure reading at about 6.5 and call it good. As far as me being able to see it from the driver's compartment it's more or less just knowing that I do have fuel pressure.... I do also have my low pressure switch I'll be using as a ground in line with my full throttle switch for my nitrous relay...