Why the wax? Never makes any sense to me. Naptha (lighter fluid) may help. Or kerosene and then naptha (to help remove the kerosene quickly).

The original 'clear' nitro lacquers were neither clear nor stable under UV. So they started off with a yellowish tint and got yellower as they aged. Some of those first 'TV yellow' guitars started out pretty white, but not for long after they were sprayed with clear coat.

Then almost clear UV-stable nitro came along, and whilst that was good for coloured bodies, it did make a lot of the necks look rather pale, so I suspect that some lightly tinted clear lacquer was then employed for consistency/continuity in looks.

Fender started using polyester undercoats in the late 60s, with nitro colour and clear coats over the top. But that then often ended up with a mixture of polyester and nitro on different parts of the guitar, so a neck could be all polyester apart from the headstock face which had nitro over the decal and yellowed with age, whilst the all-polyester neck stayed the same colour.

It wasn't until the early 80s that Fender switched from nasty thick Polyester + nitro finishes (which could be up to 1/10" thick!) to thinner all-polyurethane finishes. Now nitro on Fenders tends to be just on custom shop or special run guitars.