Yes, I used the shims to get me to an optimal (what I thought anyways, a pro I'm sure would be able to judge better) rocker arm nose to valve tip alignment. Since I was going from a roller to a sweep rocker I wanted to make sure I started the sweep in the right place to ideally center the rocker nose over the valve tip at max lift.

The shims might cause some oil to bleed off. To try to avert this I actually trimmed the shims so that the inner pieces were actually smaller (width wise) then the bottom pieces, thus forming a "saddle" if you will, so the parts match up as much as possible and leave very little free room that does not get taken up as the shaft bolts are tightened down. HughesEngines actually has a pretty good descritption of this, I went a little smaller than what they list to get better fit.

I torque down just about everything on my car with a torque wrench...the shafts get grade 8 bolts, 16 ft-lbs with SAE 30 oil.