I dont sail a supercat but i learned some things when i got a TheMightyHobie18 with a ring system:

My first problem with getting my main up (and down) was my ring was tied to the halyard wrong (the knot was between the ring and the mast).

after reading the hobie instructions 100s of times, and raising and lowering my main dozens of times (with trouble) i came to find out i was turnig the mast the wrong way.... made things much easier...

Lastly i changed to a thinner halyard... there is not tention on the halyard besides the rising (on the ring type system) so there doesnt need to be allot of strength in the halyard.