Originally Posted by tkrussell
If you can afford to pay for more copper than needed, I have no problem with that. Exceeding the code is fine, and recommended.
Depends on what kind of wire your familiar with. If this is a multi-wire cable, such as SER, then no conduit will be needed unless it can be damaged.
If your planning on using something like THHN/THWN, or XHHW, individual wires, then a complete conduit system is needed, with all the fittings, locknuts, etc. so the entire run of wire is enclosed in raceway from box to box.
Your existing ufer ground system will be fine, From the neutral lug in the main switch run #4 copper to the ufer tail, and use a irreversible connection to join both wires. This can be a compression connector.