Using AoW´s principles to fit you. Sounds great! Keep it up!
As for the reps and sets... (and please,
@Tom Furman correct me if Im wrong)
you should try and hit ~25 reps at first (5x5) and slowly over time add sets until ~50 reps (10 sets of 5 reps) and by then progress to the next excercise or simply add weight. But when you progress to the next excercise it might be to hard for you. The book suggests adding weight to the current progression (bw pull-ups -> weighted pull-ups) and start over at 5x5 again OR you could lower the reps and up the sets 8 sets of 3 reps (still ~25 reps .. yes, 24 but good enough) and slowly adding sets until 16 sets of 3 (~50 reps .. yes, 48 but good enough.
Thats the fundamental principle of AoW.
When it comes to the posterior chain Tom suggests doing deadlifts but when thats not an an option do kb swings or banded good morning for what ever reps. Its not important unless you do a swing program fitting AoW in to that, but thats a different story.