So I've got rigid insulation up, and that's all fine. But my van is gray, and in the summertime, the remaining exposed metal becomes extremely hot, and now that it's winter, it becomes extremely cold. I asked about this before, and the standard advice seemed to be to put thinsulate in the channels. But I'm confused about that -- it doesn't seem like it would solve the problem, because the metal is still connected to the outside of the van, so it will still get hot or cold. It seems like you'd need to cover the metal completely somehow to have an even semi-effective solution -- and that sounds hard to me. Any suggestions?