my experience is if you are in gusty area all sail size with 3+ camabers AO is an advantage. all the rest flat water sails above 6,5/7,0 with AO have big advantage. in constant wind above 8,0 sqm the AO is very helpful.
AO is a very good tool to get into plan in 2-3 knots lower wind and extend the top end of the sail with even 3-5 knots. its not fun anymore with a totally flat sail, but you can survive when the wind picks up...