Vinyl, what may seem like heavy working sets to some, were light warm up sets to Dorian. He was very strong, and some of his warm up sets are what some people use for working sets, and then some. He never did volume. You have guys like Lee Priest who do 20 sets for arms, Dorian was never about that.
And yes, some people do only one set, and get great progress. Some on this very board. Myself, Louden, Debaser, etc. Just about anyone following DC.
Just trying to keep things in perspective. Like I typed earlier, different strokes for different folk.