David,

You just need to make sure the system holds enough pressure for a few gear cycles during a flight and sitting around waiting for a flight. I’d check them in both up and down directions. My Kwik Fly new Rhom retracts had been setting since 74 and worked fine without leaks when I started flying it a few years ago.

One of the interesting things about the Rhom retracts is they do not mechanically lock in the up position like the Spring Airs do, but they do lock in the down position. So if the pressure drops too low while you are flying the gear will pop out a bit on high G maneuvers. That is your visual warning to extend the gear and land!! Of course back in the day we used a bit of liquid R12 in the tank to power them and one charge would last a whole flying session.

I still have two Rhom R12 can fittings.