I would like to find a good mid layer for winter use. Typically we would not be out below 20F. I currently have a waterproof breathable shell and several base layer options, but my mid layer jackets are low quality fleece. I'd love to get a Patagonia down shirt but they are pricey and only 1/4 zip. I need full zip because I tend to overheat quickly. Seems like a light synthetic or down jacket that had zip off sleeves would be ideal, but I have not seen one yet. Closest thing has been some cycling jackets. Any suggestions?