On that day ( I am not sure if I am doing that right) , because of very light winds,
indeed I did apply minimal down haul and minimal / neutral out haul.
From my observations that create maximum size belly in that sail and top is in fact quite stiff.
Because of light winds 15- 17 knots if wasn't much problem , wind at Burrum was extremely stable without any sudden gusts - that helps also.
Mast indeed is pretty random , may not be ideal for the sail.
Board used was JP Slalom 68 cm wide (118 L ) and fin BP 37.5
Definitely due to my lack of technique or wrong setup ( or both) I was slower by 2-3 knots on NM in comparison to top performers on the day, but we had very similar sail size.
Same day, same event place and wind, but other guy been able to close the gap completely