I've heard that priming (and subsequent polishing) greatly improves the durability and results using MM Metalizers
[and before anyone goes on the "use Alclad!" kick, they are a bit of a pain to use in limited work spaces]
but I'm hearing two different lines of thought:
-Gloss Black MM enamel, or
-a laquer based primer, such as by Duplicolor.
Any thoughts, tips, or general help?