I did an efficiency video of my t2. I get about 1700 shots off of a 68/4500 tank filled to 3700 psi
if you do the math then that is 217 shots off of a 13ci which is almost exactly what hogzilla gets
My reg is at 310-320 psi. just sweetspot it and you'll be fine.
TF nailed the reg issue and you can have you reg screwed out a half turn if you want to do that instead. It wont affect anything. Lots of people use those thick orings that go onto frontblocks and vertical asa's and put them on the base of their reg threads so the fit is snug and they can adjust the macoline output