Thought pretty much the same thing. A conventional pull with the feed spread really wide lol.
Pulling a no-lockout sumo really helps develop a feel for the movement in my experience.
You can call it pulling up to the knees if you like, but the height may vary for individuals. Get it to where you would just about to start the lockout portion and then go back down. DON'T use your lower back to get the weight up, and keep the bar real close when you go up and down, and lastly try to exaggerate pushing your ass out as you lower the weight (like an RDL -- it helps keep the bar close and weight off your back).