I've seen someone else go through a painstaking process of opening every baffle to add down. It's painstaking because in addition to the horizontal baffles, each horizontal baffle is split into two edge baffles and a big center baffle. I don't want to go that route.
I plan to open the edges and cut out the fabric that creates the edge baffles, turning it into a more traditional quilt design. I don't have a plan for the foot box yet. I might leave that for another time unless someone knows an easy way to get this done.