100 yd Optronics Light with red lens (it's the one you would normally attach to your scope, we don't, illegal, so we hold it)
Nunk, I think your light is a little dim. Get yourself a more powerful rechargeable spotlight and cover it with either a plastic cover or some cheap, red cellophane (you can find it at florist shops). That'll give you plenty of light to see your sight as long as the guy holding the light is within six feet of you.