Wiring from scratch

[David Cochrane]

In answer to your first question, yes it is definitely well worth running a heavy tinned-copper braid from the battery earth to a bell housing stud. The chassis has a convenient lip in which you can sit this braid. You should also run an earth wire back from each headlamp and the rear lights to a common earth point, e.g. a brass P-clip soldered to the oil pressure gauge/button pipe behind the dashboard.

I can't think of any disadvantage in running heavier wire through the car.