Tom,
First, an admission. If you're talking about polished AL or Chrome Alcad I'm a total klutz. If you're talking about other Alclad paints this is what I do:
1. For primer I've used MM gray and Vallejo light grey or black - worked for me.
2. For cleaning AB after spraying Alclad, I put a little lacquer thinner in the cup, swish it around with an old brush, dump, clean cup with a tissue, then a little more thinner and spray. There isn't alot of solids in Alclad and a single cleaning seems to work for me.
I've had fits of frustration with Alclad primer (worst clog I've ever had with an AB) and with their gloss black base coat but the lacquers spray just fine and seem to clean easily with a little lacquer thinner. BUT, I'm sure not an expert with Alclad.