You look pretty comfortable so I'm guessing it isn't super heavy for you. Your lower back looks like its rounding a little as you get into the hole and that could likely be a real issue when you up the weight.
I'd try narrowing your grip if you can and pushing your elbows forward and chest up as soon as you unrack and keep doing that until you rack the bar again. That'll pull your trunk a little more upright and help keep your back straight. I know with low bar you tend to get more forward lean than high bar but that doesn't mean you shouldn't try to stay as upright as possible (at least that's been my own experience transitioning from high to low bar).
Also, get WAY tighter before you start and slow your descent to keep that tightness; and try breaking at the hips instead of your knees (so just pull your butt back and down, knees will follow).