Out of curiosity I measured the lens thickness of my Willey X Nerve goggles (don't have other Willey's at hand right now, sorry):
Lens thickness, center - 2.4mm/.095"
Lens thickness, end of the frame - 1.6mm/.063"
A cheap pair of Portwest 2in1 safety goggles/glasses that I use for work:
Lens thickness - from 2.2mm/.087" to 1.4mm/.055"
They are rated ANSI Z87+/EN166.F
I used a caliper, so I was able to only measure the lenses at the edges. So what say you, Entropy - are those Portwest adequate enough for protective shooting glasses, despite the fact that they don't cover the higher EN166.B, which (I think) very roughly corresponds to the US Military standard?