If you have the Norvil kit there are instructions on their site (Tech) for setting clearance but I'd take that with a pinch of salt as the tighten and half turn back instruction left me with 14-16 thou clearance. I tighten and back off to a measurement (8-10 thou) and record how many holes it backed off. When you install (and no-one puts this in their instructions it seems) fit the rubber/tube assy as central as possible, screw on the fixed cap/washer/end caps and determine if it is short of pulling on the rubbers or just starting to load the rubbers axially. Ideally you want it midway between so you have appx equal gap either side as is ideal with shims. However in reality it might not make much difference, just as long as it's not heavily loaded or way short of pulling down on the rubbers.
Do the front off the bike with spacers to replicate the frame tabs. You may find that the gap varies around the tube depending on squareness of the tube faces. You may also find even with the same thru bolt torque and turns backed off when installed in the frame that the clearances change (poor parallelism of frame tabs?).
It can get very a**l trying to get these right so I would find a setting you're happy with (<>10thou) and play with the adjustable collar to see what difference it makes.
