You might want to have a look at some of the new ‘airbed’ mats that are out at the moment – lighter than self inflating mats and incredibly comfy for the weight.
Alpkit, Thermarest, Exped and Hyalite all do versions which contain synthetic insulation in the air cells – I use a Hyalite Peak AC with a karrimat underneath to beef it up when it’s cold. I find it a lot comfier than my old Thermarest self inflating, as it’s considerably thicker. I find the combo of airbed and karrimat means I can use my summer weight down bag for much more of the year, which reduces the overall weight of my pack, and takes up less room so I can carry on using a smaller, lighter sack for longer.
I bought the Hyalite cheap to see how I found sleeping on an airbed, but I’m now contemplating getting one of the Exped down lite mats as it’s a bigger sleeping surface for not much more weight. I’m also reassured that it will survive camping with 2 collies and their claws!