FWIW, you don't absolutely positively HAVE to avoid white smoke. In small short doses, you might actually want it. Even white smoke takes some time to lay any noticeable creosote down on your meat. That said, Who-dat was spot on as to the cause of white smoke. It's choked off combustion. Run more wide open with fewer lit coals.
As to the amount of smoke, if you sous vide, rapid chill, then put the butt on cold, you can still smoke it for 8 hours if you want at low temps like 225 without overcooking or drying out. The real benefit of SV in this application is that the meat has already been made tender. All you are doing is adding the smoke profile and warming it up for service. You don't have to worry about going out to check it to find that it needs a couple more hours on the cooker to be pullable. No probe testing, or bone pulling.