The green line in this pic is about where you want to rope it/cable it. Rule of thumb is around 2/3 the way along the leader.... but it's gonna be loose right!
When you are going along that limb look for cracks on top ... or even the bark lifting, look for stress points but remember, they were stress points created before this new looking leader with one decent branch now removed.
I read somewhere where they tried dynamic 11mm rock rope for cabling and after 3 years the jacket was still OK and it stood up to the UV well. Abrasion wasn't too bad either but the bad part of it was the knot ... that's where the problems were. With the rock rope they're usually around 6000lb to 8000lb strong, most the strength is in the inner core. It's a good trick when you dont have all the cabling kit on you.
I had a dual leadered tree where one side was going over the neighbours shed, did the same by using rock rope, it would have prevented the limb falling on the shed roof if it failed that's all.
