Carol Crooker had a great idea: screw a small alligator clip to a Microlight so it clips on a hat brim or visor. Trouble is, you can't adjust it up or down, and if you aren't wearing a hat or cap, you have to clip it to your eyebrow. Ouch!
For 0.2 oz, you can put elastic on a folded and stitched piece of webbing and clip the light to the fold. It will swivel up and down just like the big guys. Take a 3" strip of 3/4" webbing (or anything else, really), fold it double, stitch 3/4" from the fold, run elastic through a double-slot tensioner to provide the headband adjustment, stitch the end of the elastic to the remaining legs of the webbing which spread out against your forehead. A patch of fleece will make it more comfortable. Just clip the light to the fold and move it up and down to your heart's content. With a fleece backing, this rig will weigh 0.2 alone and 0.4 with the Microlight and gator clip attached. Not too shabby. With $3 Microlight knockoffs, its about as cheap as they come, too.