Well....I think I am officially done with glass protectors. I ordered 2 different Anker IP6+ specific protectors and tried them both. They both halo.
I have spent over 100 bucks on multiple brands and they all halo (luckily all accepted returns). Making matters worse is that each time I try another one, I ditch the plastic one I am using in the interim, so I burning through those each time I try a glass one.
I am convinced that this is phone specific with some being worse than others. I am pretty sure that if I bought a brand new IP6+ (newer batch) it would prob be ok.
I have never experienced anything like this before, but I am convinced that this is true manufacturing variability. The smartphone screens are typically ground and polished. I suspect that there is some edge tolerancing variation that is so minimal (I'm guessing +/- .0005"), we can only see it when we attempt to adhere a flat surface to the curve.
Pretty frustrated.
Positive note: I am becoming pretty proficient at installing both glass and plastic screen protectors.