I haven't made a quilt like this myself, but I think it's a mistake to believe that Hobbs 80/20 batting would make the quilt too stiff! It will add some weight, but not stiffness. What will make a quilt stiff is too much close quilting (such as micro-stippling). If you just do a regular size meander, it should be fine. I personally always like to use a fine thread for quilting in order to keep the quilt soft. (Aurifil 50wt 2-ply is my favorite for quilting on my domestic machine.) Cotton batting becomes softer with each washing too.
The only thing to watch for with 100% cotton batting is how close the quilting needs to be. If it has to be closely quilted (Mountain Mist Blue Ribbon cotton requires quilting every 2"), then the quilting could add too much stiffness -- especially if a fine thread is not used for the quilting.
Really, I do not see drape as being the issue with using batting. Weight could be, as the foundation adds weight to the top. If weight of the quilt is a concern, then Hobbs PolyDown is an option. The quilt would be soft, but lighter in weight than with cotton.
Personally, for a quilt to be used in Michigan, I would definitely use batting.
Last edited by Prism99; 06-29-2013 at 08:14 PM.