When changing the front brake pads, I'll need to compress the caliper piston. Should I use a large C-clamp, or is their another method?

 

There's a tool for that, but it really doesn't work any better than a big C-clamp - I use a big C-clamp.

DO NOT USE a big C-clamp on the rear calipers. Those pistons have to twist in because of the handbrake auto-adjust mechanism.

ps.
Watch the brake-fluid reservoir for overflowing as you press the pistons in.