I sail with an Ozzy Hook... This works great. The ozzy hook is the normal 'O' ring with a place for the halyard at the side of the 'O', thread the main halyard through the welded bar at mid height, tie off with a figure of eight/double over hand knot, then when you hoist the sail have this knot facing the mast on the oposite side to the halyard lock and this orientates the 'O' ring to engage on the halyard lock. Great idea... bit of rotation and it's a joy up and down.
With out the Ozzy Hook the best knot I found was the
(evil) thumb knot in the end of the halyard and then a half hitch onto the 'O' ring so that the thumb knot was tight against the 'O' ring facing the mast.
Lastly for feeding the mainsail into the track... if you roll the mai sail from the bottom batten (the longest batten), when you want to raise the sail put the sail over the front cross beam rolled like this, with the turns coming off on the top, then when you pull on the halyard the rolls will unwind with the luff in line/slightly forward of the mast, so feeding in with no problems...