Steve has it right: use GTO-15 feedline and a s/s cable clamp. However, an easy way to terminate the GTO-15 is with a sturdy ring terminal, with a hole sized to fit over one of the legs of the s/s cable clamp. This should be either a heat-shrink terminal or you should put heavy adhesive
heat shrink tubing over it. I actually use both! Then, there's no need for the loop....just run the wire up the backstay and connect it to the wire clamp, using another nut if you have one (best) or the existing nut if you don't.
GTO-15 is AWG14 size wire. I prefer to use yellow terminals because they're stronger than the blue ones, and to double the bare wire back onto itself for a tighter crimp connection. Take time, and do this right, inserting the insulated portion into the end of the heat shrink ring terminal. Then, put another length of adhesive
heat shrink over that.
This connection is easy to inspect and clean periodically. Leave a little extra wire belowdecks in case you have to replace the terminals somewhere down the line.
Use either short PVC lengths with wire ties or, better, 5/8" solid nylon rod with a hole drilled in the middle to hold the feedline about 2" off the backstay.