Here's another thought for you with regards to sleeping bags. You can save a lot of weight by having more than one. Remember there are more seasons than one. Many people carry too much weight by getting the warmest bag they will ever need and using it all the time. But a warmer bag is a heavier bag, all other things being equal. No need to carry a 20 degree bag in the summer (or even most fall and winter days). So get a nice warm bag like the sub kilo you mention for winter and a much lighter bag, or even a quilt or just a bag liner, for summer use.