@Pabs yeah the double bass (even 3/4, which the neck is) is a monstrosity. The bass drum is a 20 by comparison (couldn't swing the $ for one of the massive concert ones just to pull it apart).
I think with the but under the scroll I can hold a sheet of sandpaper across to smooth it, and then do the same with a shirt to stain it... But I'm at a loss for how to smooth the peg box (which is very choppy and will be impossible to stain because of it).
Any tips would be greatly appreciated (only posting again because it's worth highlighting that I actually do need ideas regarding the inside of the pegbox...) Thanks again guys.