The lenses fit perfectly on top of this style of goggle which are only about $3 on ebay. I also bought some metal stand offs to make the little adjustment knobs. I spray painted the whole thing green and my friend printed me the labels which I modified to fit the goggles.
I built straps using stretchy webbing $3 from the craft store and leather snaps $9 that I already had from building belt fobs.
These fit easilly over my glasses and the lenses actually still flip up so you can see without taking them off if you want.