^^^ this. affordable, avaialble, and flexible makes it a good choice. Don't be affraid to have too large a wire - it's never too big (except weight and cost) but can be too small.

another good option is Accel lightning cable, which is very flexible and light. it's Cu coated Al strands in a bundle. I run 2ga from battery - switch - starter. the lightining cable doesn't appear to be as widely available anymore though, most listings online are out of stock. maybe it's no longer being produced?