Hey BMB,
Welcome to the forum. neat lookin kit you got yourself there. I like your plans. Its definatley worth getting a bone nut though, but that can be done anytime or even later on down the track, same with the pups.
If you are thinking of changing the bridge, or any mods that might affect holes in the body, I would probably hold off on sanding until those mods are done, then take up your sanding again. Invariably, when modding, drilling etc the body may get knocked around a little (we all make mistakes), which only means you have to sand again![]()