You shouldn't need to go above 8-10 sets of a heavy weight ever.
That's pretty darn close, some guys might hit up to 12 sets if they just want to blast a muscle and tear the heck outta it.
Just as important as nutrition and the workout is.. the REST period.. now I have a bastersized workout bcuz I'm more of a power guy.. but if I was to gear towards BB'ing, I'd NOT be a fan of the one body part a day 6 days a week workout.. On gear or not..
Few reasons why..
first.. I feel muscles get secondary work and then get hit as a primary too soon.. I've seen some 6 day a week splits that are pretty well laid out.. but I see some terrible ones IMO too.. like doing back one day and biceps the next for example, ect.. my bi's get work when I do my back, even though I try to have that mind muscle connection with my back, the bi's still get worked.. I like more rest between using a muscle secondary and then as a primary..
second.. if your really working with great intensity and driving hard.. that intensity taxes your central nervous system.. 6 days a week of that intensity will run down your central nervous system.. off days are days that your central nervous system gets to rest and recharge.. IMO part of overtraing is not giving enough rest to your central nervous system, and that can hold back from making the best gains you can...
A great BB'ing split for intense training and rest days IMO..
Sun- Chest/Back
Tues- Legs
Wens- Shoulders/ Traps
Fri- Bi's/ Tri's/ Abs
Workout no more than a hour.. alternate exercises.. chest then back exercise, ect.. 8-10 heavy sets in the 8-10 rep range.. KILL those two body parts and let them heal..
Now I don't workout like this.. I'm more power.. upper day and one off, then lower day and one off.. lots of power sets of 5 and compound lift heavy, not much ISO work.. and I'm pretty darn strong for my weight..
But if i was working for MASS, well then I'd be doing more like the routine I described..