Looking to upgrade sleeping bag with 800+ down. Looking for a three season bag. Should I get a 20 or 30 degree bag? I have done some reading on the subject but look for real experience feedback. I do not do a lot of summer hikes mostly spring and fall. Planning to section hike Smoky Mountains north of newfound gap in mid April. Yes, I know the weather can make some big swing in temp. Mainly section hiking the AT but planning a trip out west (northwest) in the next couple of years.