I like a pretty dry barleywine but I have to disagree with the sugar. no need. if you mash long and low enough and use the right yeast it could get down to 1.015 which is about as low as I would want it.
My favorite simple barley wine recipe right now is 100% munich, about 25 lbs first runnings only. (second runnings capped with a bit of medium crystal make a nice ordinary bitter as well) mash at ~2 qt/lb at 148 for 90+ minutes no mash out.
How much wort at what gravity do you usually get from that sort of schedule?