If you have trouble getting those layers just right then these vests should come in very useful to you. Easy to get on and easy to take off should there be a sudden change in weather and temperature and with the express purpose of keeping you warm, a vest is a handy alternative to a heavy jacket, providing more manoeuvrability and breathability. You'll find a wide range here from light, mid and heavyweight, each providing different kinds of protection to the last so make sure you check out the specs!
Columbia Sportswear Men's Cathedral Peak II Vest 1519151
Columbia Sportswear Men's Collegiate Flanker Vest - Penn State University XM1944
The North Face Men's Thermoball Vest C763
686 Men's Airflight Polyquilt Vest L4W128
Ibex Outdoor Clothing Men's Shak Vest 634
Marmot Men's Leadville Vest 81100
Craghoppers Clothing Men's NosiLife Sherman Gilet Vest CMB781