This is what works for me, for both the N6.0na and N20.

I use the set up that has the twist shackle, and the little hoop to tie the halyard to on top of the ring.

Tie the halyard to the little hoop using two half hitches. This is about as compact a knot as you can get, and I've not had any problem with the knot letting go. Any attempt to use a bowline has not worked - the knot simply gets in the way.

The sail raises and hooks fine. To get it down, I have found that it helps immensely to have somebody hold the clew of the main to the side opposite of the way you are rotating the mast. Sometimes you can time it to rotate the mast as the sail is swaying to that side, but it is much easier if somebody simply holds the clew of the sail.

When we first got the N20, it had the halyard ring with the little hoop in the ring and offset. It was virtually impossible to lock and unlock the sail - it was worse than my old Hobie-18, and I consider that to be the Grandaddy of PITA mainsail raising and lowering. Replacing the setup to the above mentioned rig makes this an almost one-person and fail-safe operation, lots less cussing.