You can't tell by measuring it. That is a decent way to start, but no way is it the final adjustment. That is why you broad head tune, or bareshaft tune. It will let you fine tune the set up a bit more to your actual shooting style, arrow, and bow. There is no one measurement for every bow.

My advice would be to go with the 100 heads and leave it alone since it shoots well that way. However if you were actually going to fine tune it better I bet changing your nocking point very slightly would fix it. You could even do it with your tiller probably. Like I said, with your set up I wouldn't bother though.

The final tuning usually has to be done by you, not someone else.

I actually show that arrow as being kind of weak at that length for your set up. So it might be the lighter tip that is helping it. You could drop a few lbs of draw weight as well to check that.

If you could actually run an arrow thru a chrono and give me the speed and weight of the arrow I could get it more accurate. It's deffinately not too stiff which is why the tip change may have effected it.

Paul