Proper way to organize electrical panel
I have several questions:
1. I know you can double up 14 gauge ground wires so that 2 go to one screw on the bus bar. Is it ok to do this with 12 gauge wire?
2. On my panel the left bus bar is full but it's the only side with wire inlets still available. The right bus bar has space but the inlets are all taken. Is it ok to neatly bring some wires down the left, across the bottom and up to the bus bar? The breaker would be on the left but the ground and neutral would be on the right.
3. My siemens panel has wire inlets on the sides near the top. I've never seen these used. Is it ok to use them like I would the top or bottom?