Ok. So I am new to hammock camping. I will be doing the majority of my camping in 3+ seasons in the Rockies (backpacking and car camping). Just picked up the Warbonnet Blackbird double 1.1. I also purchased a thermarest pro lite plus (R) about a month before I decided to get a hammock. I have a synthetic bag I have used since my boy scout days. If I end up getting an underquilt, I won't be able to get at the same time as my top quilt due to cost. I do intend to still tent camp occasionally.

So I am trying to decide on a few things:
1) burrow 40 or 20 degree? It won't get below 40 much for 3 season, but always the possibility in the high country. (I obviously like the fact that the 40 degree is 5-6oz lighter)
1.5) If I go with the burrow 40, should I overstuff? How much?
2) Do I return my thermarest pad to save for an underquilt and if so, what do I do when tent camping? Or should I stick with the the pad for now since I bought the dual layer hammock?
3) Could I add pulls to the side of my synthetic bag (then run ties up to my ridgeline) to use as an occasional underquilt?

Thanks for the insight everyone! These forums are excellent.