Width is genetic. You can exentuate what you have w/ pullups and wide grip pull downs.
Thickness on the other hand is easier. Bent over barbell rows are king. Dumbell 1 arm rows are great as well. Good mornings are great for lower back developement.
I never did much rowing and I am a little thick.....lol
In all fairness it is going to come down to fiber type and compostion, so unless you can go get yours tested it is probably best to assume that thickness will come from compound explosives, just as much as isolationary moves.
well I still feel oly lifts add something to back development you don't get elsewhere. The speed and high threshold fiber recruitement, plus the unique angle of pull. Catching the weights in rack requires a stronger contraction of the back and traps as well.
Especially for all the small muscles in the back that rows and chins never seem to hit quite as well