Ping, I use both the grey primer, it helps to show up the ugly spots that will stick out after the BMF is done.
The the Alclad Gloss Black,, sanded smooth as a bubbas bot bot!
Then the BMF in which ever tone.
Living in Aus, we really dont have the access to all the funky stuff the yanks get to play with, so whenever I use paints, I try my best to use all of the same brand, and in the way the manufacturer intends.
Some may argue, but I have never gotten anything other than 1st in all my show entries, so something must be right!