One smart move is to put a
tap on the gas line so you can open and close the gas supply to the CPBF. Not cheap but it saves a lot of mess. Sometimes if you make the wrong series of hand movements you can end up with gas pouring into the beer from below, resulting in a gusher.
My sequence is:
Jam bottle onto rubber bung. Turn gas on with lever in central position
Turn gas lever to gas side
Flush using the relief valve
Tighten up the relief valve
Turn lever to beer side and let the level increase slowly, using the relief valve to control.
When near the top, turn off the gas at the little tap
Turn lever to central.
Ease the bottle off the bung.
It's also an advantage to have a short length of tube slipped onto the end of the CPBF spear so that it reaches right to the bottom of the bottle.
Edit: I've also found that for better carbed beer, if I gas up the keg to 100 and do the transfer at that pressure it's perfect for CPBF although a little on the gassy side for serving through the font.
Edit: also with this design of CPBF you definitely need 3 hands, if you can enlist SWMBO or a mate to work the wee gas tap it makes things easier.