For most of the year here in the SE, it's not very cold.
Bag = Montbell Ultralight Down Thermal Sheet(Rated down to 50*F) 13 oz.
Pad = Klymit X-Lite 6.5 oz.
Groundsheet = Trimmed "space" mylar sheet 2 oz.
If it gets cooler, or wetter and cooler, I add an AMK SOL Emergency Bivy(3.5 oz) inside the Montbell as a Vapor Barrier Layer, and use another AMK SOL Emergency Bivy(3.5 oz) on the outside, to prevent rain or condensation getting on the outside of the bag.
This really improves the performance of the system, and can go quite a bit lower in temp this way. And the totally waterproof arrangement is possible when using an inner VBL, and this keeps the bag completely dry with the outer AMK SOL bivy around it, even in rain spray or heavy condensation inside the tarp.
During the winter, it gets "less SUL" because I have to add a nearly 2 pound WM Alpinlite bag, and a GG Thinlight 3/16" ccf pad(4 oz). Plus, I have more clothes. I'm more "UL" in the winter than "SUL".
I put it all under a Gatewood Cape(11 oz), and use the matching Six Moons Serenity Net-Tent(8 oz) when necessary during buggy trips.
If I don't need full coverage shelter, then I bring my ID Siltarp 5x8(7 oz) instead.