In the picture of the H16 in downwind mode, it looks to me that even though they have some pretty decent twist, they are still travelled pretty far out. I've never sailed a spi-rigged boat and I have always been told to travel out downwind, travel in upwind. Most of my sailing is single-handed (150#) and I find that this flattens the sail for me so it helps to ease the traveller as much as possible.

Rob V.
Panama City
Nacra 5.2