^ a couple points.
Protection isnt measured as how thick or thin it is. What is being left on the surface is a minute amount of oil or polymers (depending on what your using sealant or wax) that stay on the surface of the clear. This is the layer of protection.
If anything a synthetic sealant offers more protection than a carnuba. However to say that NXT is "thin" compared to anything else makes no sense. All applied layers of LSP are thin.
The whole point of applying wax is applying a minimal amount of wax, as a minimal of wax remains on the surface when removed. Theres no point on applying it thick as that only wastes product, and becomes difficult to remove.
Alot of the products mentioned in this thread (ones by meguiars, mothers, etc) pale in comparison in terms of quality when compared to products from Optimum, Chemical Guys, p21, dodo juice, and swissvax.
Most people here are using whats found at your local kragen or autozone, when better products can be found online for a better price in some cases, or a higher quality product.
Now a couple points on layering.
If not done properly, layering (applying 1 LSP over the other) is pointless in terms of adding protection (except for achieving full coverage of the surface) Proper layering would mean to apply the wax, remove it, and let it cure (curing time depends on product being used, which has to do with the varying ingredients in those products) After the wax has cured, the panel should be wiped down, and another layer can be applied to "bond" to the existing layer. This in most cases enhances gloss, wetness, clarity, more than protection.
Now to the poster above, NXT has cleaners in it. What those cleaners do is remove old layers of protection to ensure that the NXT has a surface to bond to for maximum protection. So applying them over the existing layers of carnuba is pointless, as your just removing those layers.
What you should do, is apply NXT than the carnuba. Most sealants last longer than a carnuba. Therefore your layer of sealant is your real form of protection, and the carnuba is more for looks, as in a month that carnuba will be gone.