I agree the sail range of a given board depends on rider's weight but I don't agree figures given by Starboard were wrong.
By reviewing all of my recorded sessions since 2003, I'm using all of my boards most of the time with the largest sail simply because excess volume is just unecessary ballast for my 65 kg light weight :
- Serenity: 100% TOW with 11 m2 sail (2-7 kts wind range);
- HS105 : 70% TOW with 11 m2 sail; 30% TOW with 8.2 m2 sail (7-15 kts wind range);
- Kombat 86 : 90% TOW with 6.9 m2 sail; 10% TOW with 6.2 m2 sail (12-20 kts wind range)
- Acid 62 : 60% TOW with 5.4 m2 sail; 40% TOW shared between 4.7/4.2/3.6/3.3 m2 sails (20-45 kts wind range).
Please, pay attention that recommended sails given by Starboard for all the boards listed above were in fact much smaller : 10 m2; 9.5m2; 6.0 m2; 4.7 m2 respectively. What obviously is efficient for a 65 kg light weight rider is not for a XXXL rider, except the Serenity + 11 m2 sail combo which is still great for a 105 kg rider. Buoyancy is a key limiting factor with 105 kg...
A one-size-fits-all solution does not exist IMHO, see your 67 kg daughter on Evo 92 + 6.5 m2 sail combo. Once again, there are so many variable at play that the best piece of advice we can give is to ask your question on our forums. Somebody your size and skills might have the answer already to be shared with you according to YOUR needs.