Just a sneak preview:

For getting the right vintage color-tone you should let the UV work for you ahead: we always have filled up some of our regular NC-lacquer in 500ml plastic bottles, keeping them outside in the sun on the garage roof for getting the aged (yellowed) tint for blending the "like new" look when applying clear coats with fresh (un-aged) lacquer.

We do use plastic bottles (instead of glass) because glass absorbs a good portion of the UV-spectrum and intensity, what is not what we want here...

That´s how our "aged NC lacquer" looks after the sun did a good job for us. Notice that the lacquer was not tinted in any way, just pure mother nature (for better comparison the bottle is put in front of a white plastic sheet; the cap of the bottle is of pure white color, no Photoshop-gimmicks):

This NC-lacquer is just for blending the color, clear (unaged) NC-lacquer we use for the build-up of the layers for the top is our custom made vintage NC-formula with no plastinizers added.