Hello it has been a long time since I have posted("forgive me moderators for i have not...)and hope I can be of service.I have used things from wool blankets and poncho liners to Gov't issue and Wiggy's.The one thing I have learned is get your self off the ground.It is amazing how much a simple 1/2" inch close cell foam pad can make a difference.I don't care what the rating of the sleeping bag is.If you don't insulate yourself from the ground it will draw the heat from your body.I have seen people get almost hypothermic durring summer while using a 32 degree rated Gov.issue sleeping bag.Sure enough they were not using their ground pads.Four inches of debris or a close cell foam pad or a hammock,what ever!Get off the ground.Why do you think modern man(and I use that term loosely)has beds.The"cave man"slept on multiple furs for insulation.As the original post called it,a sleep system is not just a blanket or bag...