I am planning a late march start from springer and have a mountain hardware pinehole synthetic bag rated at 20 deg. I am concerned with getting a down bag rated at the same temperature because I am cold when it reaches 30 deg. in my current synthetic bag. I heard that it could reach into the teens in the Smokeys and around springer in April. looking at purchasing Western mountaineering alpine lite 20 deg. . Don't really want to switch out bag for warmer months. Would this be a good set up with a neo air xlite pad