So I need new sunglasses for riding and they CANNOT be polarized. For some reason helmet visors and polarized lenses make terrible rainbows. I'm looking at crosshairs and similar (plaintiffs etc) right now; my question is, how hard is it to change the lenses on these? I really like the titanium ones but like I said, they cannot be polarized. Second question. If you could have only one lens for driving (in this case riding I guess but same idea) which would you pick? vr28 black iridium seems well touted, but I've heard it's not great in the sun. Thanks!