Too much??

[Tree cutter]

No. The piston you first pushed in will pop back out when you push the second piston in. I normally just use a pry bar or large flat screwdriver to lever the pistons back in. Push one in then put a block of wood between the piston and rotor then push the other piston in. It is easier if you undo the bleed nipple as you push the piston in and then tighten the bleed nipple before you take pressure off the piston. This way you get most of the old stale brake fluid out of the system that settles in your calipers. You are supposed to change the brake fluid every 2 years so buy some when you buy the pads and rotors