Dave,

If you pull your outhaul tight before applying downhaul, most likely you will pull the sail out of the mast track as you apply downhaul. For conditions where you sail with max downhaul and outhaul, set your outhaul (with the downhaul off) with about 2"-4" of foot camber and then pull on max downhaul. You should see the foot tighten as you pull on downhaul because the downhaul also pulls on the bias of the sail.

I pretty much set my upwind foot camber at 4" for all conditions and then let it adjust with the downhaul tension.