I personally don't believe we are looking at a contradiction in the rules. It's more like an OMISSION in the rules. 1.7.2 is clearly intended to permit adjustable diamonds therefore we have omitted to include diamond wires from the 'main' rule summary.

"The rig may not be trimmed between start and finish by other means than sheet, downhaul, outhaul, traveller, mast rotation, [color:"red"] diamond wires [/color] and halyards systems."

Unfortunately, I think this omission can only now be addressed by a resolution at the next WGM. The F16GC now need a proposal and a seconder for that proposal so that it can be put to the membership NOT as a rule amendment but as a rule clarification.

Thank you MarkP and macca, I think you are both quite correct in pointing out this minor drafting error!