Personally I think you're going to want to end up with an UQ of some sort, if nothing else, for comfort. I felt like I lost a lot of the benefits of sleeping in a hammock with a full length pad under me. The pad creates pressure points that the hammock itself does not. That being said, many people get by with a pad and "wings". The major problem with the pad is that it doesn't cover your shoulders (hence the wings). Even a negative degree sleeping bag will compress under you loosing its loft and insulating abilities.
I own the Grand Truck Ultra Light and the GT Double Parachute and I must say the double parachute is 100% better. From Grand Trunk, “The ultra light is also made of polyester whereas many of our other hammocks are made with nylon. Nylon versus polyester gives more, is softer yet stronger, long story short…much more comfortable which I believe you have experienced with other hammocks. As you move up in options, unfortunately the price has to as well due to stronger materials, larger sizes, comfort, and so on.”
A sleeping bag that keeps you warm on the ground, should keep your TOP warm in a hammock.
Get a hammock and start testing. You didn’t mention how thick your pad was, but if it’s not insulated, you might want that closed cell pad too.