I've started building these 4 new necks from maple, walnut, mahogany, and yellow tarara and I have a few questions. After cutting roughly the mahogany and the yellow tarara necks, I found out that each has a slight bow - the mahogany one bows backwards and the tarara one has the normal bow as if under string tension. Should I discard these 2 necks, or is there a way to deal with the bow issues? I have done only maple necks so far that didn't require grain filling. Do I need to do grain filling for any of the other 3 necks (pretty sure I need to do it on the mahogany one)? What grain filler can I use for the necks that need grain filling? I have several Timbermate color variations, would that work as a grain filler?