^^^ Tim, I appreciate the time and effort you put into every post you make, especially the suspension- and cage-related ones
When I first saw the Sevens' adjuster, I thought the same thing you did, but after putting it all together, I had ZERO play in the plastic knob... it definitely stayed put - not saying that the adjuster was a thing of art or the best engineering idea ever, but the adjuster was positively positioned by the alignment of the perch, and the perch was positively positioned by the notched/threaded damper body, so I was sure the valving would be matched on each damper.
The springs thing - I'm not saying that a damper company will dictate what springs to run, I'm saying that for most buyers, the motorsport/venue of choice does that for you ~ and if you buy into that mentality, you're searching for spring rate first/damping second. Most people do a little math, search the forums, and then buy a set of springs... it's the same with motorcycles, and believe me, most people that I competed in WERA/CCS/FUSA with were not sprung correctly either. The truth is, the only way to really know is to run different setups (springs/sway setups at least) and figure out which compromise you feel most comfortable with, but that's out of most drivers' effort/cost range.
About adjustability - I agree that for a car that doesn't change weight, you shouldn't need to change springs/ride height once you set it for your chosen duty... but so many of us change wheel setups/aero/etc and enjoy the height adjustability - after all, these are cars that are street driven at least some of the time. I also know that a true 4-way damper has separate high- and low-speed adjustments for comp and rebound, but when you're talking about a coilover that has separate compression and rebound adjustments, every company I've seen calls that a 4-way adjustable unit - just using the "parlance of our times".
And finally, the F-D suspension "secret"... even with super stiff settings EVERYONE runs, there is enough feedback to let the pros drifting on Megan 12/10 setups compete with the D1 guys drifting on Zeals. There's simply not enough difference in how the dampers perform at the stiff end of the valving to differentiate. So for everyone out there who wants to "buy what the pros use on their 240s", its useless, because you'll never run them that stiff. That was my only point ~
In my opinion, the true quality of a coilover system on s-chassis cars comes in how well they perform when NOT set to full stiff - and I'm naturally the first to point out that I have a fantastic benchmark for all my suspension trials - a mostly stock c5 z06. Lowered using extended bolts, but otherwise stock suspension - and damn hard to beat