I like to use the WBBB with the BBO in the winter. I don't like to sleep with things that alter my breathing while I sleep and with the traveler in the cold temps, that is what I have to do. This would be a little different if I had a pod to wrap up in. Maybe next year...
I like the double layers for putting a 1/16" pad or Insul-Brite at my feet. I wish all of my hammocks had double layer bottoms.