I got my kit on Monday (very fast shipping) and installed it yesterday on a Champion 2000W inverter refurb. The rubber "gasket" that connects the airbox hose to the carb inlet on mine is an integral part of the hose, so the snorkel gasket is kind of doubled up with it, but it seems to run fine on propane. Haven't tested it back on gasoline yet.
Ran it for 20 minutes or so off a 20lb tank. No issues once I got the mixture screw on top of the demand regulator to a proper setting. I adjusted it by putting a (nominal) 1500W fan heater load on it, which is about as much sustained load as this generator can handle. I don't have a tach so I plugged a multi-meter into the other outlet and loosened the screw slowly until the engine noise and voltage output stabilized (at 118V), then opened it about another 1/4 turn just for insurance.