This will most likely be a daft question that I am overthinking but.... I'm looking for a closed cell mat to serve three purposes- 1. A back pad for a frame-less pack. 2. Protection for for a blow up mat ( I've been stuck in winter with a punctured mat before ). 3. A little extra insulation for a blow up mat. Are all closed cell mats created equal in insulation ? Ie a £5 4mm yoga mat V 4mm multimat Any other suggestions for the above uses ?