Because the helmet is going to be what everyone's looking at, I'd spend the $30 to get at least one gold-mirrored lens (available on Ebay, just search for "HJC gold" or some such). It looks good, and you're not fumbling with gold foil/CD case/I cobbled this together at the last minute from all the spiderwebs in my basement!, etc.
It's definitely worth it, even for cardboard armor, if that's what you're doing.