As a starting point try these settings for the ATR shock absorbers:
Front: Spring is 38mm (from underside of lower lock ring to the black paint line after the threads)
5 clicks from full soft. (there are 12 clicks)
Rear: Spring 45mm.
3 clicks from full soft.
That should give a fairly level ride height of about 150mm from the lower edge of the body to the ground, when two up and a reasonably soft ride. The limitation on the rear adjustment is the clearance between the lower collar and the drive belt on the LH shock. I have used ATR shocks on my M3W for about 3 years now and would say they are pretty good value.
