What's the max amount of people you personally could handle in a one shot?

A little background: I've been DMing a campaign for a little over 2 years, it just ended this summer very nicely. I went to my college's dnd club last night and had an absolute blast playing. Of the people who showed up, the vast majority people who wanted to play, only 2 people came with the intention to dm, and 3 people had to break out their emergency one shots. Apparently next week should be even more packed thanks to the career fair, I could see the terror in the club president's eyes that they weren't going to have enough DM's to accommodate everyone. I felt a little bad for them, so this morning I had an idea for a one shot with two of my friends who were players from my 2 year old campaign.

The pitch is simple, we pick up in the world of my campaign after they've defeated the big bad. These two level 15 player character have to take kids from their village (level 1 randoms from the club) on a nature expedition to see wild monsters and learn more about them. A lot of the people who are going to attend next week will be completely new, so I thought it would be a good introduction to DnD if they could let loose as kids and not worry about stat management as level 1 characters. And since they're playing as kids, it's not like I have to worry about explain the intricate lore of my world to all of them, they can ask their new scout leaders in game if they're curious. I also want to see how my friends will manage a group of people literally told to act like children. The randoms are told to just have fun, my friends have to make sure none of them die.

If you were in my position, how many people do you think you could possibly handle at the table? I have pretty good improve skills and I've learned how to plan well after 2 years of DMing. In my campaign I DMed for 4 people, and that felt pretty easy but I obviously don't want to bite off more than I can chew. My two friends are pretty reliable so I don't really count them, they're kind of psudo-co-DMing with me if you will.

Also, if you have any stories (good or bad) about DMing for a big group, I'd love to hear them as well!