IMO, I would go for one, then the other. Girth or length, if you seriously want to gain length, Then focus on that for a while.
Hanging is a game changer. Seriously.
Start with a 5 lb weight, 3sessions,5 min at a time to start.
Week 2 do first session at 5, and 2nd and 3rd, at 7-1/2.
Week 3-...