You might also consider a pan of water in the smoker to help with moisture retention. 6 hours of cooking probably a bit long. My experience on a green egg type ceramic insulated slow cooker is 4 hours max even with water pan underneath meat. It draws less air across the meat thereby less drying...
What type of smoker ? Green egg type ceramic smoker, your gas griill? Single wall steel ?
I do ribs 4 hour max in a grill dome my own home mixed rub, indirect heat over a pan with a inch of water in it. No sauce many have preferred it without sauce.
I was thinking about trying this , - my thoughts after reading through tread are not to use to much of this since it mostly lactic acid so use a low malic acid cider and add tartaric acid to give it some brightness. perhaps it may benefit with some aeration and ageing to oxidise some of foul...