I believe the o-ring sizes are:
Pin valve seat is a -006 Teflon
The smaller piston oring is a -008 polyeurethane in a 90 duro
The two larger piston orings are -012 buna in a 90 duro or 70 duro - However, I seem to recall that on my Pro regs, these larger piston o-rings were polyurethane.
I think those sizes are at least for the standard adjustable regs. There is likely a difference for the Pro V2, at least for the one in the top of the bonnet for the ball valve.
Graphite Dangerous Power REV-I
– TechT bolt engine, REV-I & Disruptive barrel kits, Prophecy V2 w/ Empire feedgate, Crossfire SS 68/4500
Maroon and Polished Aluminum Dangerous Power Threshold
– 7th Element board, TechT bolt engine, magnet trigger kit, REV-I PMD, Sly Dual Carbon barrel kit, Prophecy V2, Crossfire SS 68/4500
Black and Silver Dangerous Power F8
– APE Rampage board, VS bolt, magnet trigger kit, F8 gauge, REDZ barrel kit, Halo B w/ Exalt feedgate, PMI 68/4500
Polished Aluminum and Red Dangerous Power F8
– Virtue board, VS bolt, magnet trigger kit, Halo B w/ Exalt feedgate, PMI 68/4500