I Longarm, I prefer cotton or washable wool.
One thing you need to remember when these quilts are washed the batting takes on a bit more fluffiness. I usually dry my quilts on the line, then fluff them up in the dryer with no heat or low heat if they are damp yet and I'm in a hurry.
My bed quilt is wool and a layer of cotton, we live in WI so it is cold and we enjoy the weight of this quilt as well as the warmth. You have to remember that a natural fiber will breath, the poly is very warm.
I love the look of not prewashing fabric and then the cotton batting, the quilts really look inviting when washed.
Enjoy