Experiment by adding a space blanket between your hammock and UQ. Just read up on that ( search vapor barrier or space blanket) and make sure you know what you are doing so that you don't cause any condensation in the hammock. Main thing: keep the SB/VB on the warm side. That should get you 10 or 15*F. Then, if you get the inner VB/SB working right. feel free to add your UC for wind and rain resistance.
Find a way to run the UQ suspension up to a mitten hook or S biner on the ridgeline on it's way to the end knots of the hammock. That can be a big help for end seal and overall snug fit. Oh, and make sure the UQ is tight enough. Feel under neath and make sure there are no gaps.
Have another small piece of walmart blue pad with you to place where needed.
For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.