Tyro, Id be interested in an experiment if you are up to is. Abrasive suggested that it was the distance from the HUD to the windshield that caused the issue with clarity. I have no reason to doubt him because as rynoman03 state, he knows his stuff.
That said, do you have anyone that could help out with this? If so, go out and sit in the car looking at the hud and have your helper kinda push down on the windshield from the outside and see if it makes a difference or if you can see changes in the focus of the HUD on the windshield.
Obviously you dont want to push down so hard you break something but I think that would take a lot with a windshield, but it would be interesting to hear what the results are, even better is if you could get pics. Maybe lay a black cloth or something over the windshield and have someone press on the outside of the windshield and you take pics. Just an idea.
