Rear brake caliper question - equal piston movement on both sides? Options

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First time looking at/working on these and have a couple questions if I may.

I hit the lines with compressed air and the pistons moved but the pistons on the same side as the hard line moved much further than the ones on the other side of the caliper.

Shouldn’t they move the same amount so there’s equal pressure on both sides of the brake rotor?

If I need to get the Pistons out just remove/cut away the rubber boots and put a thin block of wood in there and then hit them again with compressed air? Should the Pistons come all the way out or just out far enough where I can get them with some sort of vise grip?

Thanks!