My experiments don't jibe w. aligning blades to vanes. I use a small profile bhead [100 gr Slicks] and w/ that type bhead from what I've read, aligning blades w/ vanes is needless, some go as far as to call it an old wives tale. I do know that concentricity is very important. And, my FOC is alot higher than Bob's, close to 19% give a point one way or the other.