I have used both leftover Devcon and wood epoxy/plumbers epoxy for hanger holes. They both work fine. There may be a very slight weight difference if that is a concern.
Yeah, once you use either its pretty much permanent. Sanding is tricky but the devcon is pretty much self leveling. (although if the bottom of the belly hole is not blocked, the epoxy will keep running into the through wire hole. Ask me how I know
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