I do fine with the x-small prolite at 8 oz. I add a 2oz 2x2 ft square REI "blue pad" for my feet, and use my pack for my head. The blue pad doubles for my outside-tent seat when cooking. I sleep curled up, so find that two pads work better because I can arrange the foot pad at an angle to the prolite. I have wondered if your body weight makes a difference. I do not weigh much -is that a reason the thinner pad is OK for me? I find that if I really inflate it, it is too hard and uncomfortable, but if I let out some air it is perfect. I do not find that all my aches and pains are a result of the sleeping pad- I have the same aches and pains the night I get home and sleep in my plush bed. My aches and pains are due to use of muscles and they hurt no matter where I sleep the night after I do a long day. I find Tylnol PM and Benydryl taken at bedtime very helpful.