I've got a Shoei XR1000 helmet that came standard with a clear visor - problem is that on sunny days it can be too bright. I can't wear sunnies as I need to wear prescription glasses. Apart from getting prescription sunnies, I was looking at tinted visors. Seems to be either dark tint or Iridium coating (like Oakleys?). Anyone have experience of using these? Do they make viewing the road a problem on cloudy/overcast days? Are they worth $80-100? Thanks in advance for your help.