Looking to replace my xped downmat 9 pump with something lighter and wider. Currently looking at the Thermarest Xtherms. Various websites have different sizes and specs for similar mats so wondering if the knowledge here can confirm things. Is the xtherm large, the same tapered shape as the regular xtherm, but longer and wider? Are only the Max versions the rectangular shape? I'm leaning towards the large version as I find I roll off my 50cm wide xped mat.