Come to think of it, I probably should have said the weight on the boat makes a difference also.

Generaly the lighter you are the quicker you need to de power and the more you need to pull on to get the sail flat. Heavier crew weight will bend the mast due to increased righting moment which flattens the sail without downhaul.

So sloops and heavweight crews on cat rigs can probably get away with less than 8 to 1 on a radial cut Mylar sail, but not the light weights, be interesting to see if Matt does better in the heavy winds once he goes 8 to 1.