I have experienced the same problem with white splotches from a can. I only use zenithals on plastic or resins miniatures now though. With older metal miniatures I prime them white then pre-shade them, because I know I will have to varnish them later and I always feel like the varnish dull's the high lights down to much even if you use satin instead of mat.
Always nice to know that you are not alone :) I've tried prime black with a focus to get all recesses and everything underneath Then I do a bad job priming white which gives a bit of shadow. But just priming white with pre-shade actually sounds better.
I have experienced the same problem with white splotches from a can. I only use zenithals on plastic or resins miniatures now though. With older metal miniatures I prime them white then pre-shade them, because I know I will have to varnish them later and I always feel like the varnish dull's the high lights down to much even if you use satin instead of mat.
Always nice to know that you are not alone :)
I've tried prime black with a focus to get all recesses and everything underneath Then I do a bad job priming white which gives a bit of shadow.
But just priming white with pre-shade actually sounds better.