They go hand in hand it's kind of tinkering device I have a couple of Crowns MkII and tinkered way more than I should the main thing is to remember what the original setting was so you can return to factory setting. You can actually increase the reg pressure and leave the hammer spring alone this will cause the hammer to be to weak to depress the valve to release the air and it will decrease your speed in more ways than you want. As far as shot count if you have your own compressor it doesn't matter, even wasting air doesn't matter its personal to each there own. I found that the reg about 110 and then I started with the hammer spring cranking it up and I was able to get 32FPE out of 22 Cal 18grain pellets which were rolling and pellet on pellet at 40 yards. Then I switched the gun to 177 Cal, and it was too much pellet flight was terrible, so I took the gun back apart and cranked the hammer spring back to original and I tinkered with the speed till the accuracy was pellet on pellet. In my opinion the amount of air used, and the speed doesn't matter accuracy is my key and that the only thing that matters.