if you have anything available thats flat and straight and about a foot long, use it for an offset gauge. hold it tight on the back of the primary so it touches both outer edges and then measure the distance of the space between the straight edge and the back of the secondary. compare that to spec in your manual. remember to push the secondary towards the engine prior to measuring.
once you have derived at a figure close to spec, with the secondary bolt installed and no shim washers, how far does the clutch slide out on the shaft? about 1/2 of the offset is allowable for shaft freeplay. using 15mm as spec, or whatever your particular spec is, the freeplay(sliding back and forth on the shaft) should equal apprx 1/2, or 7-8mm.
i would say put one thick washer behind the secondary, use two thin ones behind the bolt, and remove one of the shim washers between the sheaves(such a pain on that one), if the belt will allow it.