Depends on how much heel drop you naturally do...some are more heels down riders than others. But at any rate, if you drop your heel, it'll be on the downstroke, near or through the bottom, then lift heel to start upstroke. Neutral foot position on a bike should be slightly toes down.

How much "ankling" you do or whatever depends on your personal style..which is why the same seat position doesn't work for everyone with the same leg length.

Cleat position is also a factor.