Originally Posted by Andrew R Stewart

Next there's the question as to how this 15mm was measured. If it's with a fork in situ then the fork must be checked. I certainly have seen many production forks that are rather bad in their blade length equaliness as well as the dropouts (or drop throughs) that are not centered WRT the steerer. If the 15mm was a calculated amount based on an angular HT offness please explain your method to come to this angle.

Not trying to say you can't measure or don't understand this stuff but a number stated with little/no backround as to where it was derived from isn't a full story.