I'm a old VW guy that happened upon this '62 C10 that I'm wrenching on now.
I would certainly look into lowered spindles for your truck,then go from there.
To lower your truck that far purely with springs will open up a new world of bumpsteer and possibly ball joint bind/failure.
A few (too many) years back when working on VWs I discovered lowered spindles,they were a revelation!
They keep the steering arms at the correct angle and give a 2 1/2" drop straight off, with no bumpsteer/travel problems.
I
then installed the Sway-a-ways(VW speak)

in the front beam for the fine tuning/lowering.