That may work with polyester, but epoxy cures differently. It needs the correct amount of both parts to cure, as opposed to polyester, which only needs a catalyst to start the curing reaction. If you glaze over an improperly-mixed epoxy with properly-mixed epoxy, the exterior surface may appear to cure, but the original layer of epoxy will still lack the reagents it needs to fully cure and crosslink. Depending on how bad the original mix ratio is, the layer of resin in direct contact with the fiberglass and the surface of the wood could still remain tacky and soft, reducing or eliminating its structural benefit.