If you actually sit down and think about this you will realize that with out some complex math you will not be able to align the blades to your fletching. If you align them in a straight line with the fletching then by the time the fletching gets to where the blades were they will not be in the same air any way.

You would need to know the exact speed of the arrow, the exact distance form the blades to the fletchings, the exact amount of spin that the fletchings are imparting on the arrow, wind speed and direction (as a head wind would generate more spin than a tail wind) etc...etc... and once one variable changes then it's all for nothing.

Now aligning the blades so that all of the blades on all of your heads match each other and the arrows are all leaving the bow the exact same way may have some effect on how an arrow flys. IE: Blade down, to the right, to the left, or straight up.

But, the most important thing is to make sure that all of the heads spin true with no wobble at all.