Glad the g-clamp worked. Just checking though, have you stained and finished the body? I would not add the bridge post before the finishing coats! Also, did you add (is there meant to be?) a ground wire to the bridge post? Was there a small hole from the post hole leading back into the body cavity?

For the soldering to the back of the pots - yes, ground/earth wires would link to the back of the pots. I have not had any problems with damage to the pots. And anywhere on the back of the pot should be fine. See link for an example: https://www.buildyourownguitar.com.a...l=1#post203343

Are you using the Pitbull wiring diagrams for 2 Hum, 4 pots and a 3-way switch?

For shielding - The pups are not shielded. This came up a short while ago, I think you can shield the wires from the pups and to the switch.