As far as any style of traning goes, remember K.I.S.S. (Keep It Simple Stupid).
Ask yourself who, in all lifting, have the more impressive backs. If anyone is stuck for an answer, it should be Power and Olympic lifters. Unbelievable depth and thickness, along with width. Check out the basic exercises they do, DL's and heavy cleans/pull's. May consider training for muscle mass first, with the focus being on these Big Boy exercises for packing on size. You will give the impression of raw power, just walking down the street. You can work on refinement to the back with the usually pullovers, chins, row's, etc, after you gain the muscle mass. When you have to buy new shirts and jackets you know you have arrived. Or wind up wearing loose fitting island shirts.
DL's & cleans/hi-pulls need not be done in the usually 3X3's, 4's, 5's, etc. Treat them like a BB'ing exercise. Might try GVT, 6X6, 8X8, etc. One of the best methods (other than 10X10's) for a lot of people I know, are 7X7's. Seems to effect power and size at the same time, for me anyway. Include Power Rack training also for a quick boost in back mass.
If anyone is wondering, cleans/hi-pulls give that extra thickness to the upper back (Traps, side & rear delts ) Even biceps are involved. Train the back twice a week and make note of the results.
Or might want to do DL's one workout and Cleans/hi-pulls (take your pick..both are learning exercises and may need a little time to adjust to..but well worth it ) on another day. A lot of guy's can do DL's followed by cleans/hi-pulls in the same workout without too much trouble. Just keep the set's down to 3 or 4 an exercise. If doing advance training , like GVT, than surely have a different day for each exercise. Good Luck.