Since you asked what I think, and not for expert advice, here goes. I
think if you thoroughly seal the wood all the way around the entire
piece, you won't get any moisture in or out to create movement. Epoxy
would definitely create a thorough seal, as would "several coats of
urethane," I think. Just be sure you carefully seal all the sides too,
and you should be OK, especially if you start with dry wood.