If you are having trouble getting the sail hooked going up, try tying the knot on your ring so that it is real tight to the ring, giving the opportunity to raise the ring higher before the knot jams in the pully at the top of the mast. If you have a small bail welded to the ring for tying the halyard, run the halyard through that bail but tie the halyard to the ring. When you attach the shackle to the sail, make sure the bail on the ring is outside the halyard so the bail doesn't hit the pulley first.

For getting the sail down, try this procedure. Disconnect the downhaul and push the lower part of the sail up to release all tension on the halyard. Make sure the boom does not restrict rotation of the mast at all. I have a quick pin for connecting my boom to the mast and one for connecting rotation controls to the rotater, so I release the boom and rotation controls from the mast to allow easy and full rotation of the mast. Pull the halyard to get the ring free of the hook and rotate the mast so the ring is parallel and off of the hook. If this doesn't get it try again but rotate the mast in the opposite direction. With mast rotated, pull down on the sai until it is past the hook (a couple of inches should do it). If this still isn't doing the trick, I once bought and used a ring that is welded to the shackle that goes through the Head of the sail. This ring will move positively with the sail and you can more easily get the ring off (or on) the hook.

I hope this helps!