neck repairs

I've recently found a great looking funk unlimited JJ, however it's in pretty rough shape with a warped neck where it's bending past the 12th fret, I assume the poor thing was left in someone's hot car or something. If I go ahead with it, I'm going to get it heat treated and see what comes out...

It seems otherwise fine, apparently never been used. My best guess is polystyrene or smth when it was in storage (i literally have no idea)

I have two Fender Vintage basses - one a '61-style Jazz, the other a '62 Precision - both with rosewood fingerboards, of course. Over the years, both have developed noticeable bows in their necks. I have taken the necks off each and tightened the trussrods until they bottomed out. On the...