prop shaft alignment question

[DeWitt Harrison]

I had the drive shaft out of my 5kcstq to replace motor
and transmission mounts. I didn't closely inspect the
alignment of the front and rear halves of the shaft before
doing so but I vaguely recall that the shaft seemed to droop
in the middle.

After reinstall, working from the assumption that the
shaft should be perfectly in line, I adjusted the thickness
of the spacers that sit between the drive shaft center bearing
and the body accordingly. I ended up with 0 mm (no
spacers) from the original 10 mm spacers.

The driveshaft is definitely straight but is that what I want?
Although straight, the center bearing does sit a little low
within its rubber support. Almost every 5kq drive shaft I
have looked at since seems to droop in the center.
My car is not drivable so I can't just try it out.
Is the fabled Audi alignment tool straight? Or does it 
intentionally introduce a bit of droop into the system?

The guys at the shop say they always just reinstall the
original spacers after any work and there's never a
problem.

Once again confused in Boulder.

DeWitt Harrison
'88 5kcstq