After riding for years and thinking that my helmets fit right and everything was fine I saw the light at CSS. Josh G. asked me if I could see and of course I told him I could see fine. He inserted a piece of foam from the truck locker and behold, I could see when in my proper riding position!
I'd like to add something to head tilt. As a fitness trainer and post-rehab specialist I often break exercises down to bodyweight movements. I then get my clients into more balance type exercises. It's interesting to watch the transformation of the movements as they move into smaller muscle groups (stabilizers). Now, if you have them balance on one foot that can prove to be difficult. If they close one eye, that is even more difficult. If you want to really throw them off you have them plug their ears with their fingers. What?!? Yes, you then inhibit the vestibular system in the ears. This system also affects the eyes. We have better success with eyes that are paralell with the horizon or as close as possible. Of course that is not always possible, but you have less side effects than with the head tilted at a 45 degree angle.
Just my .02
Vernie