I have made quilts much like comforters with the high loft batting and either tying or minimal channel type diagonal quilting.
For me it was easier to do it with the backing a couple inches wider than the batting and top all the way around. Then I folded this excess over the top and treated it like binding, either hand or machine stitching it in place after the tying or quilting was completed.
If this is not as fluffy as you want a second layer of either high loft or low loft batting can be added before doing the quilting.