My take on Rancho shocks, FWIW...

They are simple HD truck shocks that guys like Calvert and the Luneacks (Tri-City Competition) figured could be used as an inexpensive rear damper for stock-type leaf spring suspensions. If I tore one apart, I'd bet the actual valving design is relatively primitive, even compared to the motocross suspension components that I worked on 30 years ago.

I, too, have a set of the older Ranchos with 5 adjustment settings, but that adjustment affects primarily the rebound (extension) damping only. The newer ones have 9 adjustments, but I expect the actual design hasn't changed beyond allowing for smaller increments in between min & max settings. Even on my junk the Ranchos are probably marginal at best. Although Dominic is faster, he runs 10" bias-plies vs my 275/60 radials which IMO are more sensitive to the chassis tune. We both need better dampers, although I'm OK with my current QA-1 R front SAs. He might benefit from better -- and more adjustable -- stuff on the front, too. But we all know the $$$ of newer technology, even for our horse & buggy suspension.