Trunk Mount Batt. Opinions needed

Ok so I plan on redoing my trunk mount Battery wiring (68 Dart) due to cranking issues. I’m keeping 1ot Positive wire Batt. To Ford solenoid then solenoid to starter. 10Ga. Jumper on starter. Removing 10 Ga. That I had from Alt. (Denso 1 Wire) to Starter relay with fusible link. Changing to diagram with CD relay. What Ga. Should I use for that (Alt. to trunk) 4Ga.?

Also, what Ga. Should I be using on the Master Disconnect wiring?

My ground is 1ot. Currently goes to stud welded to rear frame rail. Another 1ot. From stud on front rail to engine block. I plan on keeping front rail to engine ground, but also running Battery ground wire to the starter mounting bolt. Back of motor to firewall is also grounded.

Debated eliminating to Disconnect entirely mostly street driven but still a good safety item. (Bumper mounted)

Thanks

Trunk mount Batt. Wire Diagram.jpg