First follow up:
I've been out a couple of nights w/o shelter, but the temps still were only in the mid 40's. It's Florida, after all. I have to say, I love this quilt more each time I use it. With no shelter, mid 40's, I slept really warm. I was amazed how well it blocked the wind.
I'm going out again this weekend to the Sugar Creek area of the Suwannee River for some paddling and camping. I'm only taking a tarp for shelter. The low should be around 34. I'll report back again as this will be the coldest I'll routinely get it out in. It doesn't often get colder than this in Florida and I don't often get up to the mountains in the winter.
I noted before that I got a smaller quilt and I wasn't sure if I was going to take Tim up on his offer to swap it. I decided to keep it. I've simply been so comfortable with it that there's no reason to swap it.