[thabaer]

Here are the documented spec reference points.

front: Wheel center above middle of torsion bar

back: Wheel center below center of cross tube

get on a flat surface, measure the heights to each point and subtract appropriate pairs.

I don't know what year you have, but my 78-81 book 930 values are:
f: 94mm (85 US)+-5mm, max L/R diff of 5mm
r: 12mm (37 US) +-5mm, max L/R diff of 8mm

At front the axle is above the bar and at back the axle is below the tube. If there's no misprint in my spec book, the US settings have alot more rake than the RoW cars.