Go a little higher on bigger muscles: 10-12 sets for legs, lats, chest. For any muscle, 3-4 sets per exercise, determine for yourself which works better.
A good leg program from my experience would be warmup, then 4 intense sets of box squats, 4 sets leg press, 4 sets leg curls. When you want to cut up, substitute hacks for leg press. Leg extensions aren't necessary IMO, if you do hack machine squats.
Experiment with exercises of course-the best i've found for bis are cable curls (Coleman's favorite size builder) and preacher cable or free weight curls.
Always ensure good warmups-the increased intensity demands it given the added stress from cheats, partials or extra rest-pause reps on the last 1-2 sets of each exercise. Bottom line's progression in resistance and intensity. Thus, adequate warmups are essential.
And of course, extra protein has to be in place to allow for bodyweight gains that usually accompany increases in arm size.
I agree that everyone's different, but at the same time there are collective tendencies - for a majority, moderate sets using 8-12 reps per set and reasonably heavy weight is best. Of course there are exceptions, some will prefer lower reps and heavier weights, which does nothing for me and many others-the heavier weight puts more focus on the ligaments and less on the muscle, from my experience, and also increases the injury potential. Experiment with each approach for a couple of months and see what works.