Whole Ribeye is the same as Rib Roast. I’ve done it many times. It comes out real good. If you have Steve’s “HTG”, see pages 32 and 37 for step by step instructions. Also search the board for rib roast. I usually start mine in a 325-350 degree smoker for the first 30 min, then drop the temp to 225-250 and cook it until the internal temp reaches 135 for medium-rare. Let it rest for 10-15 minutes, and then carve away. Hickory wood goes very well with it.
You can also cut it in a half. Use one half as a roast and the rest cut up into individual Ribeye steaks. It’s much cheaper than buying individual steaks.