[Courtesy of Don Stackhouse - DJ Aerotech http://www.bright.net/~djwerks/]
There were two ladies at a county fair arguing about the secret to baking a prize-winning batch of cookies. One steadfastly maintained that it was essential to use exactly 1 1/2 cups of sugar. The other insisted that no, if you didn't use 1 2/3 cup of sugar, the whole batch would be ruined. Then another cook joined in, insisting that the secret was in using exactly one teaspoon of salt.
What none of them realised was that the real secret was in how those ingredients, combined with several other ingredients, functioned in combination when mixed. They had "tunnel vision".
The cook that got the blue ribbon used none of those numbers. He measured ALL the basic ingredients, but also checked the taste, consistency and texture of the resulting cookie dough, used two different kinds of sugar to get the flavor just right, re-adjusted the exact proportions of several ingredients plus the mixing speed and time to compensate for the weather the day they were baked, chilled the dough to the right stiffness before cooking, re-adjusted the oven temperature and the cooking time a bit, and in general considered ALL the factors that influenced that specific batch of cookies.
Planform is important, so is twist, tail parameters, sweep, nose shape, flying style of the pilot who will be flying the model, thermal characteristics and dimensions where the model will be flown, and a host of other factors. I would not go so far as to say any of them are more important than the others. A typical batch of cookies might use 1 1/2 cups of flour and only 1 teaspoon of salt, but that doesn't mean that getting the correct amount of salt is any more or less important than measuring just the right amount of flour!
And now I'd better get back to work on that new sailplane I'm cooking up...