My skins inside were already painted with primer and I just took some aluminum foil, cut to shape, sprayed the back with adhesive (dull side), and burnished it into place. That was in '97, well before the plane even flew and it's still there and bright. You can get metal film used by modellers, but the sheets were a bit small as I recall. I also considered chrome Monokote but rejected it due to weight, longevity, and sensitivity to heat.