I've been pondering some of the same issues being discussed in this thread so let me toss it out my situation. I have a golite ultra 20 that weighs 18.65 oz (w/o straps) and I have used it to 20 degrees with Montbell UL inner jacket, MLD ultralight bivy, and 3/8" CCF pad trimmed to 38" and was fine in it.
I've made the statement I can't imagine a lighter sleeping item keeping me warm using the same other items down to 20 degrees. This thread is making me think. Can a Nunatak quilt weighing 16 - 18 ounces be as warm as my Golite Ultra 20. If so what is the best way to spend ounces to make it happen.
Golite Ultra 20: down=9.5oz, wgt=19oz, baffle=2.5"
Arc Alpinist 20: down=11oz wgt=20oz, baffle=2.5"
Arc Ghost 32: down=8oz, wgt=14oz, baffle=2"
Arc Specialist 32: down=8oz, wgt=16oz, baffle=1.75"
The arc alpinist might do it if I use the lighter .8 quantum.
The Ghost might be close already, do I add 2 oz of down? Is it ok that it is narrower?
The specialist seems like a candidate, add 2 oz? but the baffle is 1.75" this is confusing.
Any thoughts on what Nunatak quilt with which options would get a bag that is better then my golite ultra 20 (weight wise) and/or warmth wise?
I wish I could leave well enough alone, always looking for something better.