Cook the ribs at 250-260*, and the wood should throw off plenty of smoke. Pellets will burn off quickly, and you'll have to add more. Whatever floats your boat. If you get the end result you prefer, go for it.
I use pellets for short or low smoking. Salmon or sausages for low smoking. Steaks or chicken parts before they go on the grill. You can also chop the wood chunks into smaller pieces to obtain more smoke.