Assuming the aftermarket front driveshaft is a double cardan style and balanced properly the tons should be set up so the output points at the t-case when the caster is properly set as it should. Being it is probably a high pinion 60, it's far less of an issue than trying to keep the stock 44 happy with a FAD delete, enough lift to clear 40's, and proper caster.I didn't take the time to read the entire thread to see OP has tons.
Deleting fad can absolutely destroy a t case If you don't adjust your pinion angle properly, and your driveshaft is spinning all of the time, it will vibrate until either the DS gives out or the tcase.
I retained my fad when I went to rcvs so I could run an optimal castor angle, which makes my Jeep drive better than any xj, tj, or jk I have ever owned. My pinion angle is so off now that if I didn't have fad I'm positive I would have a lot of vibration up.
I'm sure youre already aware of what I just pointed out, but I felt the need to respond to your post so others would understand what my point was.