I'm far from an expert when it comes to pinion angles, but I've spent some time playing with them and this is what I've found works for me. I'd be real interested in hearing what others have set them to and why.
Driveshafts : JE Reel
Driveshaft Angle: 10.1º
Pinion Angle: 4.5º
Driveshaft Angle: 11.1º
Pinion Angle: 8.8º
I don't have a reliable way of measuring caster, but from the best I can tell it is around 1.5º. It drives pretty good, a little light but not bad at all. I started at around 4º caster and it drove great, but there was driveline vibration. I also went down to 0º caster, but the steering was scary light and dangerous.
At the front if I increase caster (decrease pinion) the steering gets more positive, but I start to introduce driveline vibration. If I improve the driveshaft/pinion angle (increase pinion) then the steering gets too light.
With factory driveshafts I think you may get more caster without any driveline vibration. The FSM calls for >10º operating angle on the CV joints and >3º on the UJ.
At the rear, everything feels fine, although the lower spring perches are rotated back and this is introducing a curve in to the springs. If I set the pinion angle the same as the driveshaft, or close to as you don't want them exactly the same, then the spring perches are even more rotated and the curve in the springs is even more pronounced.
Some thin 10º angled spacers for the rear lower spring mounts would be ideal, and allow to set the pinion angle perfectly and have the springs straight. I know I could cut them off and rotate them, but some angled spacers would be so much easier.