If you want to follow listing, I believe both meyers hubs as well as sealing locknuts are only listed for RMC/IMC, other raceways you are supposed to use appropriate fitting. That said most liquidtight flex connectors are fine but raintight EMT fittings are useless for sealing against the enclosure wall and I use meyers hub with the RT fitting threaded into it most of the time anyway even though it isn't listed for such.