Years ago when I did my SAS I had a problem with the d-shaft binding. I called Jon at All-Pro and this is what he told me to do.

1. Clarence the CV for more droop, here is how to do it.  http://www.4x4wire.com/toyota/tech/cvmod/

2. Drill the shackles to 4.5 on center. I did this and it moved my pinion up about 8-9 degrees and I only lost about .5 of lift. I ran this way for about 2.5 years with out a problem. Doing this also puts the axle caster in about the stock location.

I am not a big fan of shims but if that is what you want to do get steel shims. The aluminum ones have a tendency to break and get spit out on the trail.

Do not say never on the dual cases, I said the same thing and a year and a half later I went d-cases and I now also have a Hi-pinion third in the front.