I'm converting a Yamaha BB400 neck. The bass is from the older BB series, the rounder Bunny Brunel shape, and is a four string, bolt on 20-fret neck. I want to use a sanding block when I get ready to level the fingerboard, but I don't know the exact radius. If there are any Yamaha experts out there, I appreciate any info on the fingerboard radius or directions to a site where I can find out for myself. Thanks in advance.