About that smoke ring, just out of curiousity, are you using some kind of oil or oil-based product to help the rub adhere to the meat? Rubs and spices are oil-soluble and I'd been using canola to help it stick to the meat and penetrate down into it. The downside is it seems to block the formation of a smoke ring, which I confirmed on a recent rib cook. I did two racks, prepped and cooked identically. I used a mustard slather on one and oil on the other, with everything else equal. The oil ribs had a faint pink ring. The mustard ribs (garden-variety French's yellow mustard) had a much deeper, redder ring. Only one cook so I can't confirm this, but just a thought.