Sounds like Dave has a great setup for instruction. For me, I have to share the range with other shooters. We have 3 roll around bales that we can position anywhere on the range for short distance work, so can get beginners shooting. BUT, I have to be really aware of what the other shooters are doing, and kind of have to become a de-facto range captain. In this situation and depending on the shooting level of my students, I feel I can safely work with 3 or 4 students. In order to not affect the other club shooters, I will stop my student's shooting when I see the others are done with their end, even if the students still have arrows left. I can call the range clear for arrow retrieval and start again when everyone is back behind the line. If you don't have moveable targets for short range work, then having dedicated instructional range time is the only way I see to do it.
I also try really hard to schedule lessons during times that are less busy if possible. Right now all we have available is an 18 lane indoor, 20 yard range so have to share what we have. Our club members are very accommodating, I must say.
Unless I have the range to myself, never more than 4 students for me. IF I do have the range to myself, I'll work with up to 10.
Arne