Anyway, I read an article by Bill Winke, where he said the optimal weight should be between 6.5 and 7 grains per pound of maximum draw weight. I draw 65 lbs, so that would put me in the 422-455 range.
Optimal for what? If he didn't quantify the answer, I disagree with it. Ashby would say that 650 is the minimum you should be shooting and I tend to agree with him because of his vast amount of experience and knowledge on what it takes to make a kill with a borderline hit. If your talking about silent shooting, then heavier is also better. If you're referring to penetration, then heavier is better.
So, why does he say 6.5 - 7 grains per lb is better? If he's saying that it's better than 5 grains per pound, then I agree. If he's saying that it's better than 8 grains per lb, then I disagree.
Whatever you do, don't lower arrow weight, without a real good reason. This is especially true if you've taken the time to get the perfect arrow spine match with your setup.