Revell 1/16 vw bus

This is the process.  Clear the tires with a water-based gloss clear, like Future, or your gloss acrylic of choice.  Apply decals,  let dry, clear them with flat clear of choice. 

Or to simplify things,  put the kit in a box, addressed to me.  I'll give it a good home 

Are they vinyl tire or plastic ones?

In styrene I'd be sore tempted to use a pale sky gray as te undercoat for the whitewalls.  Or maybe a medium blue for the more 'modern' less-wite whitewalls we see today.

For vinyl--dunno, probably depends on te vinyl used, and ow flexible.

Checking Scalemates, there's a review of the T1 and (in German) calls the kit tires "rubber."

Luckily, you get a spare tire upon wic to pratice (since you can stow it "good side out" to need.

Shoot, just noticed they make a Karman Ghia.  Dang it.  Owned an Alpine T1 at 17, and a KG at 18 . . . could get spendy.  Sigh.