In arguments like these I advice somebody like yourself to develop you mathematical models further, they still allow conclusions that are in direct conflict with eachother and as such lead to errornous conclusions. Your models are not yet well defined.
I have a model that takes into accounts all influences like changes in angle of attacts etc and the one clear conclusion was that with each reduction in sailarea the boat because disproportionally slower. Even at 9.00 sq. mtr. (my 3.90 mtr design) I could achieve 10-11 knots at maximum. Which is fast but a 5.00 sq. mtr. sail area at a significant lower aspect ratio will be well below 10 knots (around 6 knots or so).
My experience of using windsurfing rigs on a multihull does not match your mathematical models, from your comments it appears you have developed your own VPP. It does not seem to be giving realistic results. Perhaps it does not scale well.
Look at the international Moth Length=3.4 beam=2.2 SA=8m2 similar total displacement to an F12, with a windsuring sail it goes significantly faster than your models would predict.
