Here are some random pictures and drawings I have on the spring shims. The first 5 pics/drawings are all from GRINGELTAUBE and are going to be the most helpfull I'm sure. The others are some I had taken or made . Myself and some others basically ended up making zero degree shims by machining them down. Attached is a drawing I made for someone who wanted to make some by welding flat stock and drilling. Perhaps it will be helpfull to some others.
Either way the pictures should make obvious that not all spring shims/perches are the same and what works for someone will not work for everyone.
My experience was that lower tire pressure, toe-in near zero, and spring perches machined nearly flat (0-1 degree) is what gave my truck a nice ride. Tire pressure played a pretty big role, even just 5psi made all the difference as I was experimenting. But that was for my truck, probably will be different for most others.
Winches, bobbed trucks, cargo boxes (m35a2), Van boxes (m109a3), tire size-brand-style, runflats, weight of the wheel/rim, wheel balance, shocks..... all these things will have an effect on how a truck rides and handles.