Darn lol I'll have to get some bolts. I am
Unsure of how you measure to find out what shims you use too...
Probably no reason you could not tap the holes yourself and reuse the old bolts instead of purchasing the self tapping variety?
Back lash is set by varying the left and right side shim thickness and end play is set by the total thickness of both shims on each side of the ring gear.
Measuring for end play is a matter of pushing the ring gear left or right and noting how much movement it has with a dial indicator when the ring gear is installed and cover torqued to specs.
Back lash is the space between the teeth where the ring gear mates to the pinion gear. It would be nice if they specified backlash tolerance as degrees of free rotation of the pinion or slop in the gearing. Actual measuring of backlash clearance can be done with Plastigage to check it. It's quick and easy and nearly as accurate to just compare the degrees rotation of the pinion with a known good preset (new) differential once end play is set if you have access to one.
I'll set end play without the pinion installed so I know what the total shim thickness of both shims needs to be without the possibility of interference of the ring gear contacting the pinion. To set back lash then its a matter of subtracting .1 mm from one side and adding .1 mm to the other side to get backlash in spec.
From the manual (Agreed not very clear)
"Gear Case Side - install a 1.3-1.4 mm shim and
tighten the bolts to 28 ft-lb. Verify backlash to
be within a range of 0.28-0.38 mm (0.011-0.015
in.) and end-play to be within a range of
0.10-0.20 mm (0.004-0.008 in.). If not within
specification range, reselect shim until backlash
specification range can be verified."
Note that there is a slight (tiny) bevel on the inside inner lip of a shim. That bevel must face towards the inside or towards the ring gear