The ability to depower or flatten the main via backstay may have been a bit over-optimistic concept. but then the original traveller track was choked. This was designs from 30 years ago. 16 true may have been one of those edge points for moving into a #2 which was a required sail 30 years ago. Some of us like the #2 a lot over 15. I think it is perhaps a 145+?
Flattening the main was not a problem, mostly I would have liked more backstay to help reduce the headstay sag as we were definitely at the top end of the #1. The upside is that the J/30 is a Freightliner uphill in those conditions_.
