I keep the regulator set at about 100psi.
As far as the fittings & hose, here goes: I have a 3/4" that's adapted down to 1/4" NPT so that I can connect the regulator, 1/4" NPT to a ball valve, then I have my 1/4" female quick connect. I use a 50' 1/2" Goodyear rubber hose with 1/4" NPT...