Beautiful write up!
An easy way to push the rear piston in (if you don’t have a C clamp) is to insert a screwdriver into the inspection slot between the outer pad and the caliper and slowly pull outward.
Do this before you disassemble or remove the caliper and make sure the piston is moving smoothly.
Mine probably need replacing and were not moving smoothly so I worked them in and out some by repeatedly pushing the piston in with my pry method and pumping the brakes to push the piston back out.
After I get the piston moving freely, then I remove the caliper.
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