Since you bought the higher energy model, I think you got what they advertised, just that you didn't realize you bought the full blast version.
And now that I've been a lot deeper into this, and found more information, yes it might have been easier to get a long screwdriver and adjust it down. My only concern is not having the o rings to seal it up if the regulator needed to come out. I know they bind on the threads at the receiver end, and I had an issue trying to get mine out the fill cap end. So I just left it in place while I was doing things.
I did get a little pressure creep overnite, about 500 psi. Not too bad when all things are considered.
I do need to get a long screw driver, probably a little later tonight. The 2800psi that it currently sits at is slightly high for my gun, I normally get better velocity on the third shot which would be around 2650psi. Most likely I'll need to adjust mine down a bit. My rifle has only had the ports opened slightly to a #1 drill (about .225 inch) and the hammer seems to be striking the valve nut so I don't really get a change in (old tube) first shot between about 4.5 turns out and 3 turns out.
I'm also still running the stock valve return spring and stock poppet valve. Need to look for some poppet modifications and different valve return springs for a slightly lighter spring and where I need to clearance the poppet.
Other work you are going to want to do:
Polish the barrel. Unless you are really lucky, or they did this at Pitbull, there are many sharp edges on the rifling. Some polish on a cotton pellet back and forth will help reduce lead build up. I built a simple tool for this that I can show if you are interested. Just a brass screw, some brass nuts, a metal file, and a handheld drill are needed to make it. Works from 357 up to 50 so far.
Lube or powder coat your ammo. Again lead build up prevention. I've been powder coating, but I also recently bought some tumble lube that is supposed to dry to reduce the mess, haven't tested yet.
Mark the threaded "plug" on the hammer spring. I used an engraver to make 4 lines at roughly 90 degrees and a mark on the receiver. Makes it much easier to get back to a known number and does not functionally damage anything. They should have come standard with these markings. I may decide to do 8 markings but right now I'm not seeing much difference between quarter turns. Maybe I need the Pitbull spring installed, I have it but haven't installed it.
And lastly, you may want to start casting your own ammo. With the Benjamin Nosler going for over $1 a shot, it can pay off quickly. Going to need to go another $125 to $150 to get started with lead pot, a mold, and some pure lead. Really should add a siding die or 2 and a simple press but there are a few designs that will drop "close enough" to work without sizing.
Lee 356-125-2R cast bullets have been really accurate for me too, I think I have them up to 185fpe after my mods. These tend to drop right at .357 so you could lube and shoot directly out of the mold. I have two other designs ranging from 155 grains down to 84 grains, but haven't gotten any accuracy info because that's when I started having barrel issues, and then winter hit. Need to cast more for testing. One is a Lyman design with and without hollow point (155 and 125 grain), and one NOE design that is hollow or flat point (88, 86, and 84 grain depending on the pin used).
That said, you should buy a few boxes of that Benjamin Nosler, of the few boxes I've shot they were directly as advertised. Right at the power level (185fpe stock gun before mods) and as accurate as I could be with iron sites at 50 yards. Always within a 3 inch circle until the barrel started to lead foul (my first barrel was a turd). I have most of 4 boxes here for comparison testing. Expensive but a known quantity.
