Daves article is a little confusing for sure... take point 8 and 10... how can u have your hips at optimal height and your shoulders behind the bar at the same time? short answer is you can't if you don't have the right proportions.

I'm positive if you met Dave in person he could clear it up pretty quick, it's one of the problems with articles...

Konstantinov pulls exactly like Rippetoe would recomend except he pulls round back... but his lower back isn't all that bad.

Konstantin has done interviews where he states he couldn't pull over 700 until he started pulling round back, and he's also never had a lower back problem... tho he has had injuries in other places.

Reality is, nobody pulls a big conventional with good form... end of story. People can pull big with acceptable form, but I've never seen anyone pull a true 100% single conventional and not have their form look like complete shit.

Just keep the back static, lower back tight, shoulders slightly rounded and you're good. Sooner or later some douche that can't pull 405 is gonna run up and tell you your form is terrible... it's happened to me... but that's the game.

Sumo, is a whole different animal though... your form should look pretty good on that, and just from the position you start in, it's a lot easier.