I forgot to post that last week I went out on a friends fishing boat and tried out the SUM with different lenses. Turned out to be a good day to try as we went from fog to very blinding sunlight to a very early dark due to the fog coming back.
I'm not sure of the names of the lenses so will give them names and I'm sure John or anyone else who knows better can inform.
The lightly smoked lens was the best all rounder for the day.
When the fog was down at midday the sun was hitting it giving a very harsh light. I found the yellow lenses to be the best for this as it still gave good visibility (for what you could see in the pea souper) wail also taking a good edge of that migraine inducing light. Only thing to watch with these is that your brain can turn Nav lights into a few different colours, rather like the white balance on a digital camera.
When the fog lifted and the sun came belting through, reflecting off the mirror like water the very dark lenses got snapped on. This was great and allowed me to jockey the boat with out any eye strain.
When the light faded I switched back to the lightly smoked but in the end had to take the mask off. At this point a totaly clear lens would have been good. Although after getting home I realised the yellow may have worked better.
The lenses take a second to change as long as you have them handy.
I've not had chance to test the SUM in wind, rain or waves yet but going off what has already been said on this thread I have no worries. I also bought one of THESE
to wear with it. Still waiting to test that out too. But I think Nos is trying that kind of gear out on his bike.