In the absence of a dedicated paint cleaner, cleaner-wax oughta better prep the surface as compared to NXT alone. The combo of a cleaner-wax topped with a "straight" (i.e., non-cleaner) wax is time-tested; it works.
IMO it's better than using the NXT alone and at least you'll get some use out of the cleaner-wax. In the future you can get better products and see if they make a worthwhile difference.
IIRC, Mike Phillips of Meguiar's has used NXT over top of Meg's #66 (a professional-line cleaner wax).
Using a cleaner-wax on wheels is *VERY* similar to the popular approach of using Klasse AIO on wheels. AIO is really just a "synthetic cleaner-wax" that has sealant instead of wax for its protective ingredient.