Hah! I knew you’d have my back on my comment (intended pun).
You can see that improvement come Olympia time, but he also gets better at posing too. Great example that one can improve a strong body part into a legendary body part.
Maybe that’s the point; Dillet was never going to have a legendary back because the genes weren’t there. But for heath he took a good (as far as pro) body part into something legendary. I’m sure it wasn’t easy but it’s still rare-ish, and even more rare for it to be the back (where it seems you either have always had it or you’ll never have it).