I have a KB hood mount also, but I sure wouldn't use it to set my fuel pressure (it is a good reference when racing but not accurate enough to set baseline pressure)
go to your local Pep Boys/Autozone/Checker and pick up a fuel pressure gauge with a hose that will screw on to your fuel rail that has some decent resolution (like 1 lb) and accuracy.....they aren't that expensive ($40 or so) for something that important...plus you can easily extend that hose and check your WOT FP without a permanent gauge