My grandmas & aunts are the same way. It gets down to the high 60's at night & you'd think it was sub-zero weather by their descriptions "it's so cold I can feel it in my bones"... ummmm, really?!!!! We would kill for 60-degree weather as a high up here in Illinois.
Ok, off my soap box... I use the same W&N for their quilts as I use for the ones I make to sell up here. I like wool, but since they launder their quilts more frequently (up to 2x/week) down there, I probably wouldn't use it. Definitely have to make sure everything can go in washer & dryer because of how easily mold, mildew & pests grow down there. If they don't dry the quilt all the way in the dryer, it quickly starts to smell mildewy.