Slickery- It sounds like you didn't take offense at my post, and I'm glad
I always apply more than two coats when layering, and perhaps that colors my opinion/results. And yeah, I do think that it's a good idea to let things "cure" for a while if you're going to try that.
For reference, when I topped 476S with Souveran, it was about three applications (not to say "layers"

) of 476S applied several days apart. Last one sat for a few days before I applied the Souveran. I spit-shined three/four applications of Souveran using chilled Griot's SpeedShine for the spit. This was on robin's-egg blue RM brand b/c, a repaint on my old Volvo wagon. Can't say how long the results lasted because I gave the Volvo to my niece-in-law soon after detailing it. And anyhow, the spit-shining (IMO) mitigated the solvent action of the Souveran anyhow.
On the layering and durability issue, my comparisons were between two/three applications and five/six, the latter exhibiting all the "wax is still OK" indicators for much longer. The applications were always at least one day apart, often longer as I have a shop where works-in-progress stay clean. (Yeah, all controls such as uniformity of timeframe/etc. were observed

)
Oh, and applying 476S (four applications) over 845 made for much better durability than two applications 845 alone (same timeframe adjustment, etc.), but that's got a few too many variables for my taste.
One application of 845 shocked me with it's lousy durability! Same with one application of KSG for that matter.
If you decide to do this testing, I'd sure like to hear back about your results, even if they are utterly different from mine. If you don't decide to do it, I understand completely, as I myself don't do a minute's worth of this stuff anymore unless it really needs doing; guess my intellectual curiosity got satisfied a long time ago, now it's just a chore that needs doing now and then. But I still enjoy reading about the results that others get.
Less- There are some very good posts about spit-shining, I suggest you search for the one by
Nick T.
The general idea is like when you spit-shine footwear: you apply a coat of wax the regular way and buff it off. Then you spray some water/QD/"spit" on the surface and apply more wax. Buff this application until it basically disappears instead of letting it dry and *then* buffing. Repeat until you're sick of waxing

The wax that "disappears" builds up on the surface.
Servicemen/women can tell you how well it works on footwear; they end up with a *THICK* coat of shoe polish (I do the same sort of thing with my dress shoes). Yeah, car wax is different from shoe polish, but it's the same idea.
A variation that I call "pseudo-spit-shining" is to just spray the "spit" on the surface, apply the wax, and then let it dry to a haze before buffing. I get more spherical beading and a slightly better look, but not the same increase in durability. I attribute this to some degree of solvent action on the paint (perhaps what
Slickery is talking about) or maybe it's some side-effect from the QD :nixweiss But the durability is *still* better than just settling for fewer applications of wax (I only do this with #16, not sure how it'd work with other waxes).