Fretboard to bridge clearance measurement
 

I have built about 10 guitars and I am now building a bass for the first time.

When running a straightedge down a fretless fretboard and hovering it over the bridge area, how much clearance do I want over the body surface?

12/32" More? Less?

I used my Fender J as a model and did 7/16" for FB to body on the fretless I built. It ended up being a bit less after the FB was radiused.

However much you want, but 3/8" sounds pretty good.

3/8, is standard for many aftermarket bridges such as Schaller and Gotoh, Hipshot A is about .400.

I set it for just higher than the lowest possible height of the bridge, so it depends on the bridge.