On our hp dinghy (past tense) the block/traveler was above the single tiller and it had a 6' tiller extension for each side, that's right, two of them.
I'm thinking the Wave may be an application for thinking outside of the box. How about a little three or four foot aluminum job on each side, mounted right to the tiller, or just inboard of the joint on the crossbar, sos it can just "flop" straight aft when not in use?