Hi jeff,

Sail area is 164 sqft for the F16 vs. 150sqft. However the F16 rule limit mast height and luff length. Maybe you have to add mast tipp weight to fulfil the mast tip weight rule. If the A-cat mast is designed to the limits, I would doubt if it strong enough for a crew of two and spi.
At the end the strongest argument is that you lack more than 10% sail area. What about letting the rig as it is and add a spi, get a true F16 mast and main, use the same spi and you have a nice two rig option?

Cheers,

Klaus