Greg,
What is the diameter of your ring?
Originally I had a 2" ring (Nacra F18, 2005), and it was really difficult to release the main. I also tried everything, finally I changed the ring to an older style one, diameter 3", and it is ok.
I'm using the Murrays Aussie Ring with the loop in the inside of the large ring offset (see picture attached). The inside diameter is 2 1/8 inches.
I'm THIS close to rigging a Bosun's chair to hoist myself up to release the bleedin' sail!!!
Please pardon the colorful language.
Greg