I've not used Floquil paints so I can't address whether or not it would work as a primer for Alclad. I put down a coat of Testors light gray, usually FS 36270, and if I shooting Alclad aluminium, a coat of gloss black. For any other shade of Alclad, I put down a coat of gloss gray on top of the FS 36270. Murph's drying times correspond with mine (see above). What I like about Alclad is that you can mask over it without any adverse side effects. I'e used just about everything as a masking agent, from 3M Magic Transparent tape to Parafilm, without any problems.
Dick McC