Put one under every screw and cut them flush, if you need to ground a switch leave one long enough after going under the screw to reach the switch.
Most ground screws can accept two wires as well, there is usually two raised pieces next to the screw, put one wire on each side and tighten it down.
Originally Posted by GeorgesAA
Basically attach each bare cable to its own screw and not bond them together with a wire nut. I'm asking because this would save me some room in the box.
The fact they are both securely attached to the METAL box means they are bonded together.