On the 390#. i believe you're somewhat shallow all through. You're also letting the weight come forward at the very bottom. It looks to me like at the bottom your hips stop going down but the shoulders still go down (and thus forward) and they also bring the knees with them a little.
About the 285 set... stance looks a bit wide, but i'm not really seeing the asymmetry you're speaking of.
Also in both (but especially in the 285 set) you move your mid back a fair amount. Meaning you establish your extension after you start the rep and then loosen it before you lock out. Some people seem to do that more than others. Don't know how serious a fault it is considered... i'm guessing not too much since i don't see it called out often.
The 2nd set at 390... pretty much the same thing as the first but it's just really slow. Isn't it hard to do it that way ?