My normal teaching mode is two buddy pairs of students and my buddy is my AI. I'm all set. On occasion I will not have an AI, just one pair of students. I dive differently, usually that means carrying a pony in addition to my usual stuff. If I'm taking a new diver out on a checkout vs a team member that I trained and with whom I dive regularly ... again different approach, different site, shallow, and I prefer to do that as part of a pair of buddy teams or a trio. Same if I'm diving with my 11 year old ... best as part of a team of two buddy pairs or a trio. What it gets down to is thinking not only about your own abilities and limitations but the abilities and limitations of the diving team that you are part of. If I were insta-buddied I'd similarly want to dive as part of a larger team that has some members that I know are competent, but then I take seriously my commitment to provide assistance to any buddy who requires it.