Driveshaft: how much clearance?

^^^ this.

this. and i cannot stress is enough: ask them how they want it measured. and then be specific with who you're talking to.

i had a driveline place that one guy would want them measured one way, and the other would want them a completely different way.
Agree completely. I asked them how they wanted me to measure then I provided those measurements. Did that directly to the owner through a phone call, though don't know if he was the one to make the shaft... doubt it. Possibly something was lost in the translation.