Originally Posted by
McCreed
I have no experience with any Wudtone products, but if what c0ffinspire89 has said:
I would suggest that using a rattle can polyurethane (eg: Cabothane) over the front of the headstock and decal would be the go.
Tru-Oil has a proportion of poly in it as well as being an oil based product so I would make the presumption of it being compatible with Wudtone.
The spray poly will have a much higher solids content than any wipe-on finish, therefore allowing a much quicker build up to bed in the decal paper.
Also, based on my assumption of compatibility, I would not use lacquer over the Wudtone as lacquer has a much stronger solvent and may likely not play well with a turps based base coat.
It should go without saying that testing on scrap like you've done is the best way to ensure what will/will not work.