Stoker , I'm not sure if you got your answer , my stoves paper work ( Waterford STanley) has -04 water gauge, but the stoves fire fence has -06 WG embossed on it , with a nice fire my max draft is -06 chimney will run around 250-290* when it's time to reload chimney temp will be down to 200* with a draft of -04 . Do you have 2 stove thermometers? 1 for chimney and 1 for stove body ? That will help you figure out where to set your baro, -04 draft is the # I see the the most on this forum , by having it set at -07 you may be burning a lil more coal than you have to, but I don't think you'll damage anything! Good luck.