Evan and I must agree to disagree--unless I'm mistaken, I'm following Ben's rules. I ALWAYS face the sun when I do it so I don't overestimate my CYA level.

But, it is more important to always do it the same way, to be consistent. Then, even if the numbers have to be a little higher or a little lower for you, they will always be consistently so and you will be able to compensate.