Sorry, I do not understand that.
Did you use this set up around 0*C?
Snugpack underblanket, roll mat, 3,3 kg military sleeping bag and thermal clothing?
May it be, that your sleeping bag is more than 20years old and totally destroyed?
With thermal clothing I use the Snugpack Special Forces 1 sleeping bag on the thin german army folding mat comfortably till 4C, but it works for me till the border of 0C too, both in the bivvy bag. In the forest, in the open, without tent or tarp, without fire.
This sleeping bag weights round about 1kg. Yes, it's the newest technique, yes it's relatively new, may be I slept only 200 nights in it in the last 3 years. (I own several different sleeping bags, I didn't count.)
Yes, I am a relatively hard gui. I am used to be outside.
But compared to your set up???
What's the point?
Do we need far more insulation in a hammock than on the ground?
Is your Sleeping bag to old? Are the fibres broken?
Or what's the point here?