I found a good deal on a Polaris jacket online. Trouble is there are no returns and I am not sure about sizing. This is a shell-type jacket. I normally wear an XL and the Polaris sizing chart seems to be ok for an XL. Anyone have a Polaris jacket and if they run big or small? Given that it is a shell, I was thinking about going one size bigger than normal assuming I would need to wear a thicker midlayer underneath it. But I am not sure if the shell jackets are sized to accomodate that already.