There is another application for a mirror that makes it a bit easier to heft that extra ounce into your PSK. They are great for illuminating dark spaces.

I learned this while working with members of the Arizona state agency dealing with mine rescue. We needed to search some mine shafts and they showed up with highly specialized, technical equipment, the mirror from a medicine cabinet! It projected a very strong beam down into the shaft and lit it up far better than any lamp. I have since done the same thing with signal mirrors illuminating building interiors, cave mouths, dark overhangs, etc. Lots of throw, but no scatter whatever.....