I found the brown lensed aviators ok providing I was not doing anything too strenuous.
From your profile I would assume you're going to be working without aircon. If so you may find, as I used to, that glass lenses are too heavy and slide off the moment your nose gets even the slightest bit sweaty.
This is particularly true of the stlyes fitted with bayonet arms although Dave Clark type headsets do help clamp them on.
I started using a pair of lightweight Bolle glasses and even though my days of loading a C402 out bush are over I still use them. They provide 100% UV protection, wrap around slightly to prevent glare getting in the sides, are less likely to break and if you lose them they don't cost as much to replace.
Course, that's just my opinion <img src="wink.gif" border="0">
[ 03 January 2002: Message edited by: Flintstone ]</p>