I have been playing for over a year with my A-5 using CO2 and am ready to move up to compressed air. I can find out which would work best for my A-5. I am really looking at the 68/4500 from Crossfire, but I don't know whether I should get HP or LP? Which would be better? Because if HP will work without me having to buy a reg or something, then I'd rather get that. Any good advice would be appreciated. Thanks.