I think there’s a logic to both and I’m no expert.
Without arguing over mass vs weight, if a 2400 lb car weighed the same at each corner the tyres would support 600 lb each and if they were 600 lb springs they’d settle slightly less than an inch (because some of the weight is unsprung) while the ride height would drop by slightly more (because of suspension geometry). Let’s guess the two variances cancel out and so the body did drop by an inch. Two fat ladies and a tank of fuel might add another 600 (none of it unsprung) so the car would drop by more than an inch etc. G forces on dips and rises would alter the effective load and the dampers stop it bouncing around. The actual stroke of the damper piston is not huge.
My single coil-over per side solid axle has much more unsprung weight and far less sprung. The axle is too heavy for me to carry but the alloy rear end is not. In my case, I used dampers with threaded spring seats to set ride height and from memory the Demon Tweeks catalogue had nothing like 650 lb coil/-over springs.
I figured that a full 15 gallon (Imp) tank will add 100 lbs and myself 200 lbs, so an extra inch drop beyond static ride height (sharing 300 lb between 2 springs). I haven’t driven it yet but it all looks/feels right on 2 springs of about 150 lb/in at the back. The front is TB and being much lighter the car will feel a bit stiffer on standard bars, due to lower forces.