rudders binding on my 1982 nacra 5.2 had me puzzled for a bit too until i looked closely at how the cross bar is linked to the pintles but 2 universal joints. traditional universal joints a position where they won't work smoothly and that what was happening to me. solution is to just twist the tiller extension a little to move them out of that area

having a block on the jib halyard allows you to change the tension on the jib halyard easier. tight gives a flatter sail for better upwind sailing and loose gives a fuller sail for better downwind sailing

do you have the pivimatic rudder kick up system mentioned in the pdf manual?