Well you definitely don't want to pre-finish everything before assembly! Unless you can mask off the edges and datos that will be glued. The clear coat will impede the glue. My suggestion is to build the speakers, then use a foam brush to apply Tung oil. Mask off any ares you don't want finished (speaker flanges, binding posts, etc...). Apply the Tung oil lightly. You don't want any drips. Let each coat dry for 24 hours. Buff all areas lightly, by hand, with 0000 steel wool, between each coat. (Lowes, Home Depot, etc...). Towel off steel wool residue, apply the next coat, repeat 4 - 5 times. You will have a gorgeous finish.