Someone recently sold a Hell's Bay Waterman with these seats on it. I was unable to get him to respond when a couple of us asked about them (not sure why). Does anyone have any information or a similar set up? I'm about to start a Heron 16 build, and I'm pretty sure this is the only set up that would work due to size limits on the back deck. I'd love to have some back support if possible, so any help would be appreciated.