I garbled some of the information in my previous post. Instead of "conventional oven," I should have written conventional pit. I expect you'll be cooking in the 250F - 275F range, rather than the posted 350F. Finally the hot/slow stuff really doesn't apply unless there's a gas or electric fired pit in there somewhere.
With meat as inherently tender as a standing (and/or prime) rib roast, there's not much benefit to going low and slow. If your cooker can hold 350 with good smoke, you might as well go there. My previous and current cookers were and are a little more restricted than that -- the smoke wood burst into flame if I had the fire going like that; but different pits work differently. I like the 275-300F range for beef -- and convection being what it is, would knock the temp down 25F. So, 250-275F. Not to make things too confusing, but if the convection oven can hit higher temps, the hotter the better -- all the way up to around 350F with convection on. You don't want or need a super even cook with standing rib. If the meat on the bottom (at the bone) and the top (the "tail" aka "cap") gets darker and more cooked than the eye -- that's a very good thing from both the standpoints of presentation and taste.
When I smoke big pieces of meat like a whole standing rib, I don't burn smoke wood all the way through the cook but cut it off after a couple of hours, tops -- and that goes double for expensive or delicate cuts like prime rib or tenderloin. Think of smoke as a seasoning like salt, you want the right amount -- not too much or too little. On the other hand, if it's a wood fired pit, don't worry about it.
You want to watch your times on rib roasts. Cooking times are a function of thickness as well as weight and they may cook faster than you expect. Use some of the extended cooling time as your cushion to get things on the buffet at the right time.
Sorry for the confusion,
BDL