David,
I cook only spares during competition. Have a few trophies to prove you can match the tenderness of BB with spares.
My process is pretty basic. I use a rib rack, trim the ribs to St Louis style (ending up about the same size as BB).
My target temp is 220 - 240, ideal is toward lower end of range.
I allow 7 hours total. I leave them alone first 2 hours, then spray with mixture of apple juice and basalmic vinegar. I also start with bone ends (opposite brisket bone end) down. At 3 hour mark, I spray again and rotate position of ribs in rack, moving outside ribs inside, etc.
At 4 hours, I start looking for meat to be receding from end of bone. Once it is about 1/2 inch, I turn them over, so bone end is facing up. Spray again and every 30 minutes thereafter. I sometimes will sprinkle a little more rub on in case I feel too much has washed off.
At 5 1/2 hours, tenderness is checked by wiggling bones, toothpick through meat, meat receding 3/4 inch or more. I then begin basting with mix of mustard, maple syrup, and brown sugar.
I watch this step closely to make sure they do not burn. Repeat at least once in smoker and once again when you pull them
At 6 hours or so, I remove from smoker, let rest for 30-45 minutes, then I glaze them with my BBQ sauce over hot coals until crispy. Let rest 15 minutes, then cut up and serve.
Always yummy.
Dale