If you want weight to your quilt the add a layer of Warm & Natural with your Hobbs 80/20. Remember heavy quilts are much harder to wash and dry and can become uncomfortable.
If you want to use wool, you will get a warm but lighter weight quilt. I suggest Hobbs Tuscany Wool or Quilters Dream wool batts. If you want a really high quality wool find alpaca batting. Alpaca is expensive but is a wonderful fiber to work with and quilts up like a dream!
If you are wanting a fiber that will breathe but still keep you warm but not too warm, you might want to try bamboo batting. Once again, it's expensive but is very nice to work with.
For adding a bit of weight, you might look at Fairfield batting 60/40 or 50/50 blend batts.