This is my first build. I'm working on a p-bass, pine, with quilted maple veneer top. As I prepare for a burst finish, what color/tone grain fill should I use? And will the grain fill accentuate the bookmatch veneer seam? It appears really tight, but this is my first try at this sort of thing so I don't know what to expect. Thanks in advance.
Maple does not require grain filling as there isn't much grain/pores to fill, it's a diffuse porous wood. If you want to highlight the minimal grain that is there then you dye the wood (usually darker) then sand back before applying your chosen main colour. This will work better than a grain filler on Maple. The colour of the highlight will depend on your main colour. Obviously as it's a veneer be careful sanding! There should be plenty of info on the above procedure on youtube etc.