If you're not looking for a total overhaul, you could also just try putting the band around your thighs and do your warmups. It would help activate the muscle needed to keep your knees out and it would cue you to keep your knees out.
I can't tell if you're using them or not, but knee sleeves help with this to. It's not that they force your knees into position, they just help you become more aware of where your knees are and what they're doing. Unrelated, but they even help me find parallel easier so I don't cut my squat high or excessively bury it.