Yes, I thought your form looked solid, too
I didn't mean to suggest that your knees were caving... Just that you might find you get a stronger squat out the hole if you use your glutes hammies to drive your hips forwards and up while simultaneously really shoving those knees out harder.
In one of Ripptoe's training vids where he is teaching hip drive he doesn't seem concerned that the dude is good-morninging (if that is a word) it up. Apparently he does worry about this though, as soon as the hip drive is reliable and automatic (chest up!!)
I find myself getting the feeling of pulling myself up out the hole with my quads rather than pushing myself up out the hole with my glutes / hammies, too. I guess that was what I meant by your weight being forwards - that you seemed to be using your quads / knee wobble rather than your glutes / hammies with your knees shoved out harder still.
I've been doing a lot of bar work with a resistence band around my knees which seems to really help me use my glutes / hammies to initiate the ascent and really drive my knees out hard. I certainly don't pretend to have a perfect powerlifting low bar squat - but I do think it is helping.
I'm finding I get a sticking point where it takes a bit of time for my glutes / hammies to kick in properly on the ascent. The temptation for me is to lean forwards a little (to deload the hammies / glutes, I think) and use my quads to pull me up more... I can grit my teeth and deal with the pause, though, and they kick in eventually.
But I certainly don't have an amazing low bar back squat! Or any other style of squat for that matter