Heat grill to between 200-250 degrees F.
When grill is hot, place ribs on a metal tray and generously rub each slab with ¼ cup of rub.
Place the ribs on the grate bone side down, shut the lid, then bring the temperature back to 250 and cook for 1-½ hours, flipping halfway through so both side caramelize and get a nice brick hue. The ribs will be done when the rack is very flexible and the meat pulls slightly away from the bones.
Remove from grill, wrap in foil and allow to rest at least 10 minutes before slicing.