Thanks Douglas for the advice. Having sold our old heavier bags and being left only with a light car camping double bag for now, we're wide open to choose a new sleep system. Have to decide between down and synthetic, which isn't really a choice in the Northeast from where we moved due to all the wetness. The Sierra Nevada is quite dry by comparison.
Lean toward single quilts for the versatility to use mine if I'm on a group trip, and to allow us to sprawl out.
Which quilt temp rating would you get for 3 season Sierra Nevada, and which for winter Sierra Nevada? We have been lightening up over the last several years and have our clothing system pretty well dialed-in already.
For clothing we'd bring for 3 season we have Ibex light merino Woolies long johns and Patagonia R1 Hoodies, as well as Patagonia Houdini wind jackets and insulated caps and/or light Hind balaclavas (about 1.5 oz). We also carry Montbell Thermawrap Hoodies. We also have light rain jackets and at times light rain pants (Golite Reed pants). Light gloves as well. This should help us use a lighter sleep system, especially if we use the Thermawrap parkas as part of our sleep system.
For winter we take heavier insulation, including slightly heavier Ibex merino long johns, Arcteryx light softshell pants, Patagonia R1 Hoodies, Patagonia DAS Parkas and Patagonia Micropuff pants, and a warmer hat to layer over the Hind Balaclavas. Throw in heavier gloves as well. With insulation like that we should be able to use a lighter sleeping bag/quilt, but it would have to be large enough to accommodate the layers.
I tend to sleep warm early in the beginning of the night and only feel cooler closer to morning, and my wife sleeps colder but tends to retain heat better into the morning.