Main halyard
You have a problem which seems to be univseral with all older C30s. Check the archives for many submissions on this subject. I have a 1988 C30 that does exactly what you describe--or did. I found relief by raising the main from the mast instad of the cockpit. I think the routing of the halyard is much, but not all the problem. I cut an exit hole about 6 feet up th mast and I haul the halyard hand over hand until fully raised, then tension with the winch. It goes up easy until the tensioning part, and this is where the binding occurs, but the sail is up. I also put a swivel block at the base of the mast and took the halyard directky back to the winch avoiding the deck turning block. I notice you installed new shives and I also planned to do this, but don't think that's the problem. I think you may be onto the real cause and that it's an internal binding on something. I'm satisfied with what I did to make the boat easier to rig, and quit the struggle. Good sailing Ron B