Head Tilt and Draw Length

[Camp Creek]

I'm getting back into the longbow after many years off and trying to tune some douglas fir shafts.  They're too weak and I keep cutting them shorter and found that I'm shooting a much shorter arrow than I expected.  Sitting at my desk at work with a yardstick, it seemed like I should be shooting a 34" arrow; until I tilted my head forward which then measured 30".
I have to admit I never noticed or thought about this before.  It just seemed natural to tilt forward and look down the arrow more, but I realize now that's at the expense of a lot of stored energy.  I'd love some thoughts on the best form before get too far down the path with new arrows.
68" longbow with a bit of deflex/reflex that I made over 30 years ago.  65# at 29", shooting split finger and anchor corner of the mouth.

Thanks

[McDave]

I discovered the same problem by accident.  I was comping a new bow and was disappointed with the results.  So i tested a few other bows that had previously tested at higher velocities, and they came in with lower velocities than they had tested before.  I thought that my chronograph had gone out of whack, so I sent it back to the factory to be recalibrated.  They told me it had tested fine, but they sent me back one that had been reconditioned anyway.  That one also came in with the same lower velocities, so I thought they were just BSing me and had sent back my original one instead.  I wrote the nice lady at the chronograph company, and she assured me that they would never do that, and that they had in fact sent me back a reconditioned one.  So I borrowed a friend's chronograph, which showed the same thing.  Finally it dawned me that the problem was the nut behind the wheel: me!  I had slipped into the habit of tilting my head, and my head tilt was costing me draw length and arrow speed.

When I returned to shooting with my head in its normal upright posture, my draw length and arrow speed miraculously returned to what they were.  That said, I've seen some really good 3D archers shooting with their heads tilted.  They are probably doing this in order to reduce their point on distances by getting their eyes closer to the arrow, and all their shots are at distances of 35 yards and in where the loss of speed really doesn't matter.  So I suppose it's really your choice, but whatever you do, do it consistently.

[Camp Creek]

Thanks.  I assume before I go much further with arrow tuning I need to establish a consistent form with a consistent draw length, and like so many other form related issues, what you do is not nearly as important as whether you always do the same thing, especially on a live target.