I do like Hobbs wool batting, but I have been using a combination of a layer of warm and natural and a layer of poly and get very good results. The poly is much warmer than just a single layer of warm and natural. I can get the crinkle look if I want by not pre- shrinking the cotton batting. I also like the weight of cotton so the combo of the two works for me. The combo also drys much faster because of the poly. Finding the Hobbs wool ... at a reasonable price can be a task, unless I stock up when on sale on line with free or reduced shipping.
When I double bat ... I use a Long Arm pro as wrestling one bat through a machine is tough... two would be a real problem.