I cannot vouch for what you should do with the headlights but for the tails if you use VHT do a light coat and then a second coat and that should be plenty of VHT. Itll be enough to notice but it wont be overdone. I just followed a write-up on here about how to do it and I think it involved wetsanding between each coat and then applying multiple coats of clear and wetsanding I believe.