Beef rib question

Ah, back ribs! Depending on the actual amount of meat on the rib bone, it can be easier to go by pull-back for smoke time, foil time etc.Smoke until you see just short of 1/4" pull-back, then foil for an hour or so and check pull-back again...foil for another 30-60 minutes depending on what you see. My hand-cut full slabs of beef backs have taken over 7 hours with straight open grate smoking, but that's a heavy slab of meat on the rib. I would figure closer to 4 hours total for the ones you have...they have a thinner layer of meat, so they  shouldn't take very long.

Eric