I used a Mountain Laurel Designs Spirit Quilt 30 with a 3/4 length Ridgerest closed cell foam pad cut down to body shape.
The Spirit Quilt is Climashield Apex insulation with a momentum 90 shell and weighs 19 ounces.
The ridgerest is closed cell foam and weighs 6 ounces as trimmed.
I used every piece of clothing under my quilt in the Smokeys where it reached the mid twenties.
I was just warm enough there.
Everywhere else on the AT I was more than warm enough.
Caveat: I seem to be a "warm" sleeper compared to most other hikers i meet.
It took me a while to trust that the synthetic quilt would be warm enough. Once I found out it was, even when damp, I never worried about it again.
EDIT: Thank You Anna!