Background: I am still in my transition to the light side. I have come from a 65 lb pack to a 25 lb pack. (7 day trip). I am not an expert, but I get expert advice from this site.
I am in search of a better sleep system for my needs. Currently I use a synthetic (allergic to feathers) 45 deg mummy bag, a uber-light, and my empty pack under my legs. This was fine until I slept in my first shelter on a cold night. I froze my @#$ off. I slept in my tent the rest of that trip. I have read the articles on sleep systems on this site and have some ideas. (more confusion though)
I could add a thinlight pad under my sleeping bag or add a silk mummy liner for minimal weight. (adding versatility to changing weather conditions)
I could modify the bag to convert it to a top bag, but after reading the articles, would this really help.
Of course, I could just get a better rated bag, but I don't have unlimited funds and do have spousal opposition to big $$ purchases. ( many $$ spent on transition to ultralight already)
I would appreciate any nuggets of wisdom you could throw my way.