Well, it's a true pearl yes, but it's in an opaque base. The first paint job I ever did was a translucent pearl, or candy color, I will NEVER EVER do that again. It's total hell to get the color on without banding or light and dark areas.

You have a number of different questions here, and not all of them are simple answers.

It'd help I have had pics of something you are trying to remedy, and can offer better information. I've done a ton of research into paint, and painting to do my own work, I approached it like I do most things as an investigative writer.

I'm not quite following your order. An etching primer on bare metal used to be the standard, but with DTM epoxy it's better not to use it as the acid in the etching primer doesn't get along well with the epoxy.

I'd weld in your panels, grind the welds smooth, I'd then put a 2-part glazing compound along the weld, and feather it into the panels.

Are you able to keep the car totally from any weather exposure the entire time you are working on it? Mesa, AZ is at least dry so that helps.

Then I'd use an epoxy primer designated at DTM (direct to metal). Right on top of that I'd spray a dark grey or black sandable primer (epoxy primers are not easy to sand).

I'm not sure about "sanded to 80" do you mean 80 grit? If so, I'd say, I would never use 80 grit on anything I am not using that to take the previous paint entirely off.

I never use more rougher than 120 grit, when using factory paint for flattening and leveling.

I've never heard of putting epoxy primer over primer, it's always the undercoat.

I wouldn't use anything rougher than 220 grit to sand primer, especially if you are going to shoot a dark color. I'd then go over the entire surface with 400 grit. Then surface wash with a solvent surface washer, then spray your base color coat.

Why would you mix your color coat with clear? Sometimes people tint slightly the clear coat with a tiny bit of the base coat paint, but I would not do that if there is any pearl or metallic in the color.

Why would you sand your base coat? I would simply shoot the clear coat on the base coat within the topcoat time window suggested by the paint manufacturer. If you do clear coat, two-stage paint, which actually isn't how Surfblau was done at the factory. Surfblau is a single stage paint, with no clear coat from the factory.

You can sand and buff the clear coat if you want a mirror finish.

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1983 W123 300TD US spec Turbo engine, with Euro bumpers and manual climate control, and manual transmission.