I've had some pretty good luck since the last post, both on exterior and interior paint colors.
I have and have seen several brands of vintage color chip charts and they describe the metallic in the paint in various terms. Metallic, Opalescent, Iridescent and Poly. Poly is the description on Ditzler charts (pittsburg plate glass), currently known as PPG. The Ditzler chart numbers have also been the only useful info to anyone I've spoken to.
Everything the local PPG supplier was coming up with had metal flake that was too bright which I've seen before on vintage cars, and the color was never quite right.
I stumbled across a company called TCP Global who's claim to fame is a huge library of colors, quite a bit of it from vintage records. They said they could match my Ditzler number for Mediteranean Blue Poly and could make a spray out card for $45 to look at. Not having a lot of faith, I ordered it anyway and they absolutely nailed it both in color and sheen. Turns out they knew about the bright metallic issue and still order the grind of metal found in vintage paints.
I could've ordered enamel, lacquer, PPG base/clear, or their house brand Restoration Shop base/clear which is what I ordered. I was working with a really knowledgable guy named Jimmy who thought this was the first Aero project he'd done. He said he remembered the new Aero very well when he was in high school.
After fixing me up on the exterior paint he did a lot of additional searching and found a Ditzler list of Willys interior colors, which on my dash and the 2 parts car dashes I stripped is Gale Gray (dark) and Sherwood Gray (light) as well as several other interior colors. I already have my exterior paint and today my interior colors arrived with a copy of the Ditzler info Jimmy found, as well as his card, attached below.