I think that what you are describing, the way the eastern Europeans tend to squat in the IPF, is a pretty good way to squat, whether the bar is high or low. I would prefer it high, but even low, its a good way to squat. Breaking knees first then sitting down and back is, IMO, the way to go. If the bar is high you will tend to drop the hips more straight down, if the bar is low you will tend to sit back a little more, just because of the length of the lever made by your back. If the bar is high the knees should tend to be still moving forward even as you get to the very bottom, if the bar is low, the knees should not move forward after about the midpoing, roughly.