I have a snugpak softie chrysalis autumn which I have had a few years, it is rated comfort at -5c to 10c, it has what they describe as a jumbo baffle which you can unzip the main zip & zip up the baffle to increase the size, label says chest 165cm plus baffle. The pack size is ok at 19cm x 21cm & weighs 1500g, so might be a bit heavy for what you want. I have never been cold with this bag, I am a very plus sized lady & I have never felt constricted in this bag, quick google suggests they don't make this anymore, but the spec of the expansion 3 is similar
edited to add rough measurement across bag at shoulders is 90cm