I said nothing for or against the Ginkgo Cloud or other solid or semi-solid support systems designed to absorb energy sans springs or soft rubber mounts. (At least, I don’t think the Gingko uses springs; I could be wrong there, and if I am wrong, then I would not use the Gingko under a SOTA tt.) Yes, you DO have a way of knowing without trying (contrary to your sentence above) why spring on spring can be a very bad idea. (It’s never a "good" idea but by chance one might not create serious problems.) Just read up on Simple Harmonic Motion and spring rates, etc. Can you get away with it and using subjective judgement go away thinking there is a benefit? Sure. Happens all the time in this hobby. Consider this thought experiment: you have a nice modern sedan that has a spring and damper suspension conducive to a nice smooth ride down a typical imperfect highway. Now put your sedan on a flatbed trailer, strap it down to the bed, and ride in your car while someone else drives the trailer down the same highway. The trailer has its own suspension with its own spring rates and damping. You will be tossed around a lot more in your car tied to the trailer than you were when your own suspension was ameliorating bumps in the road.