Right. You want to be sure that the beer carries all the CO2 it is supposed to have into the bottle and you want to get as much air as possible out. I watched the B^3 video and he was silent on the subject of pressure. The way the B^3 gun appears to handle the purge cycle is by continuous flow rather than the pressurize, dump cycles I have used so I'd say setting the gas for a few psig above what you carbonated at should work fine.
Oh, I don't have their CPF. I have the one with 2 ball valves (one for gas, one for beer) and a bleed valve. Looks like what he's doing there is just barely opening the purge valve after opening the beer valve.
We'll see how it goes anyway.
Primary: Nada Damn Thing IPA Secondary: ESB Kegged: Jack Schittenweiss