Yes, both my 6 & 7 string clamping cauls are failed necks. I figured the board surface is the right length and shape and it's planed flat, so they make perfect cauls. Have been using them for years now.
Re the blue: I tried talking him out of it, his response was the whole guitar is built around the idea of the blue and not the other way around, so the blue was not negotiable. Oh well. At the start the blue really annoyed me, now not so much. It's grown on me. Not enough I'd do it on my own guitar, but for this build it has it's place in the theme.