I'm by no means an expert, but I've done brake pads like 20-30 times (SC part of that count) and I flat guarantee I could move those pistons in just a few minutes unless they are really seriously f'd up. I have never had a problem recessing or moving the pistons back into the caliper.
What works....typically used:
1. Large Screw driver with a piece of wood as both protection and to gain leverage, protection less important if you are careful and if you are tossing the pads and resurfacing the rotors, YOU ARE RESURFACING the ROTORS, yes, I thought you were. (I use the large screwdriver to pry against the rotor and the calipers just nudge them enough to get the whole caliper to slip off into my hands, then use the following so not to risk things.
2. Large C-Clamp, slowing turning the screw to tighten the clamp and press the pistons back in.
3 . Large Channel Lock Pliers (big !Removed! ones too)
Sorry, but I don't know w.t.f socket you guys are talking about, but if its easier, cool enough, but the stuff I use is often in anyone's garage.