Heels should always be in contact with the floor and there should never be a question of them raising - it means your whole mechanics are wrong, regardless of the type of squat you are doing (power, oly, narrow) - most likely you are inflexible or maybe have strength imbalances. These issues should be addressed before the squat can be used as an effective strength builder. I would recommend developmental hip, ham and calf stretching and maybe some lower back arch work and a few months of lots of overhead squatting to get the sqatting posture correct. (I dare anyone to try to rise up on their toes in an overhead!)
DaveTSI has a good powerlifter's competition squat by the looks of things but your heels will NEVER come up at all when your toes are angled that far out. Your knees must come forward a bit if you're doing a regular stance Oly style squat, and that isn't a bad thing if you are sitting back and staying nice and upright.