I don't know if this will help, but here's my ole Slonoma
with 2" drop spindles 1" front colis that have settled to
around 1.5/ 1.75". In the rear is a drop by pulling a leaf
and 2.50 angled blocks. They were 3" but I had em cut
down by a machine shop. I didn't do anything to the driveshaft
on my ride. The trick is to get the rear end to sit back as far
as you can on the spring perches before you tighten it down
and to make sure you tighten and TORQUE the u-bolts in
an x-pattern. I torqued mine down to 95 ft# and ck em once
every 2/3 months. Truck rides pretty good, but I did replace
the shocks with Doetsch Tech drop shocks. Goes down the
road pretty smooth, but will scrape if I hit a large dip or
bump, but as far as it hitting the trans or the rear end by
way of the drive shaft, that hasn't happened. I've had the drop
on for a yr..This pic was taken right after I dropped it. It's
settled more now and sits a bit lower..