[BIG BLOCK JIMMY]

After 2+ years of staring at the 3 degree caster shims I bought from offroad design, I'm ready to install them. I'm attempting to cure the invigorating "dartiness" and I'm hoping the shims and an alignment will do it.

Questions:
Are 3 degree shims sufficent or should I get 4 or 6 degree shims?
I assume to increase caster the thick side of the shims points forward.
The shims came in a three pack, so the differential side will have one on the bottom and one on the top opposing each other, correct?

I also have the rear axle offset blocks to center the rear with the wheel well as HEMI stated. I'm sure there's a thread on that already, but I can't find one.