I am interested in this too. I get a shimmy from time to time and assumed it was a balance issue. However, I watched a Poundstone video about Glutes and he said your butt is in control of lateral knee motion. Which would make me think it's a butt issue if your knees move laterally.
I am Anton Zdravko Martin!
Best meet lifts: Sq 150 Kg (330 lb), Bench 120 Kg (264), DL 160 (352) @89 Kg (197)
Best gym lifts: Sq 375, Bench 280 (pause), DL 385 @205 or less
Goals beyond my wildest dreams, 600 Kg raw total, 200/160/240
Hack away at anything which isn't essential. Do what you love, and do it often. Fazc.
Everything competes for recovery so more assistance is not always the best idea. miked96