Easy-Hooking: Here is the real deal. Forget the sponge and wood bits.
I have been very happy with Goop on my ring's shackle: it is polyurethane glue with solvent, like ShoeGoo but much softer.
The trick is to put Goop in place on the shackle so that it cannot fall over sideways, and the ring is held in the correct position to hook properly.
THUS: Put some on and let it get a bit stiff (10 minutes), keeping it in place with a little masking tape. Then put the sail up, tipping the A-cat over if necessary to hook it, and go sailing. When you come back in- the sail is MAGICALLY in the correct position for unhooking and rehooking for some months.
Goop shrinks a little, so put a bit more on to restore Easy-Hooking. Goop does not really need to be permanently stuck to the sail's grommet