dont waste your time, they are all massive in size and the bit you sleep on is a waste as there is no air in it to no insulation. The matteres will keep the bottom warm or get one of the marathon runner tin foil blanket things and put that down under the matt you will be surprised how much heat it will bounce back up, then look for a down quilt, I have the thermarest one but there are loads to choose from now, and it is warm as toast, I got a fitted sheet that fits the exped and it has poppers on to attach the quilt and the whole thing is good enough for camping in sub zero tempretures
What sheet did you use with the Exped? Been looking for something to cover mine?
TA Steve