Sounds like you know exactly what you need to do! You're bending over in the bottom of your squat, you just have to do it way sooner. I think your depth is inconsistent because you're fighting your body's desire to bend over the whole way down, then you finally let it do what it has to do and you sort of crash into the bottom of your squat. It's almost like you hit a sticking point in your descent. If you get bent over sooner it should smooth the whole thing out, let you control your descent, and find consistent depth more easily.
Basically, knees out, butt back, and bend over IMMEDIATELY when you start your squat.