Re: Do you ride in the cold?
Good idea with the sweatshirt, should work out just fine. I do something similar with the foot bags lol. I use 13 gallon (tall) trash bags, so they go up aways. I lived on a 45' sloop for awhile, learned some valuable stuff for cold weather. Really cold, like -20°F, it can get rather brisk, up off the Canadian coast.
Layer One: closest to the skin. Polypropylene, like UnderArmor, or old school long johns. The point is to wick water away from the skin, a layer of ice on the skin is the last thing you want.
Layer Two: the insulator. Goose down, heavy knap wool, dead air space is the name of the game here.
Layer Three: the shell. Water resistance is the word. Goretex, rubber slicker, whatever. Keep the water off of the rest of it, and you. Nothing is water proof only resistant, and rarely permanently. CampDri sucks, all the spray on stuff does. Use a synthetic fabric, I really have to recommend GoreTex here. The stuff rocks, sheds water as well as a traditional slicker, it's lighter, and breathable.
Anyway there's my two cents.