Have you posted pics of the Bach since the retrofit Mark? I'd love to see it with the mod.
Iome, you have mail.I came up with these measuremnts with help from George, OldmanC, and others - I think it is fairly accurate. One thing to consider is that as this is drawn the reach to the nut is long - it was for me and I'm 6'1" with long arms. You may consider moving the neck pocket back, maybe 5mm, towards the rear and moving the pickups on bridge spacing by that amount as well - this would help the reach to the first fret.
It seemes like Gibson always leave a lot of space behind the bridges on their basses.