thanks for the info. So far so good. I removed the pistons by banging the caliper on a big block of wood. Used a rag for a bumper for the pistons.

the big pistons look shiny and uniform. Some surface scratches that I may be able to take out. Anybody got a method to chuck these in a drill, to help polishing them? All the little pistons have pits. I plan to replace them.

The caliper cylinders look okay to my eye...not really a machined surface, they just look cast. One of the cylinders even has a big long pit in it near the bottom, which looks cast in place. I'm thinking the cylinders are acceptable.
Yes, that is a question.

Inside the rubber rings there is no rust. Outside the seals (under the dust covers) there is much rust. I'm thinking of using hydrolysis to clean these. Of course I don't want to ruin any seal which may exist between the halves of the caliper, and I won't take them apart. Hydrolysis makes rust removal so complete and easy...but I don't want to do damage either. Any thoughts on this?

I did get the brake cylinder assembly lube. Mine came from Raybestos, and I felt very lucky to find it. Rare, around here.

One more question: My master cylinder drained out. This job is taking a while. Do I need to do anything about that, or just wait until I have the rotors and calipers back on?

TIA, Rick H.