In most situations, I would say one 22" in a combination with gasser or other 22" or even 18" would be fine. But in your situation with having to cook for 10 or more people at a time regularly and having a WSM to take care of other cooks if needed,plus easier to use one grill if you mainly grill ..... Yes! 26er is what you need imo. And down the road if you ever wanted or needed 22" or 18" to add...... they are much easier to come by than other way around used.