If you are running a business, this is a good problem to have: Your product is crazy popular, enough that word of mouth is basically the only advertising you need. People are willing to pay top dollar, and demand is through the roof, even two years after it launched. Of course, with such success comes a desire to scale to maximize your reach, which presents its own challenges.

That’s the enviable dilemma the producers of “Hamilton: An American Musical” find themselves in. They’ve currently got shows going in New York, Chicago and Los Angeles. Rehearsals have started in London as well.

Jason Bassett is the production supervisor for all the “Hamilton” productions. Bassett’s job is to make sure everything’s ready when the curtains go up. He’s been with the show since the beginning. Marketplace host Kai Ryssdal asked Bassett what he knows now that he wishes he knew back then. The following is an edited transcript of their conversation.

Jason Bassett: Well, when we started on Broadway, we didn’t staff up enough, because ultimately what we realized is that “Hamilton” is an incredibly physically demanding show, and we sort of treated it like we treat every other Broadway show, which is you have a certain amount of offstage people that cover the onstage people.

Kai Ryssdal: Covering, you mean like understudies?

Bassett: Yeah, exactly. Some people we call “swings” because they go on for the ensemble, and other people we call “covers” or understudies that go on for principals, and we had probably six people offstage. And what we realized is that because the show is so physically demanding, that the onstage people are more inclined to get hurt or exhausted or be out. So now we have, like, 12 people offstage.

Ryssdal: I have to tell you when I saw it a couple of weeks ago here in L.A., I was blown away by how dynamic it was onstage. I mean, there’s a lot of moving around and jumping and all kinds of stuff.

Bassett: Yeah, the ensemble never leaves the stage really. I mean, they have a problem, you know, finding a place to go to the bathroom in the middle of the show if they have to.

Ryssdal: I hadn’t thought of that, but yeah. You also use something called universal actors, is that right? Tell me about that and how that worked?

Bassett: Yeah, we call them “universal swings.” Swings are like an ensemble person who is offstage. Like, a male swing will learn six different ensemble tracks onstage. It’s not easy.

Ryssdal: Because there’s so much motion that’s crazy.

Bassett: Yeah, it is a little crazy. It takes a unique person to be a swing, an incredibly organized person to be a swing. What we also found is that as we opened a couple of extra shows, what we what we thought would be a good thing to have in our back pocket would be to have someone who could travel to any show at any given time. And that becomes an even more specialized sort of swing in that there are tiny nuanced differences between the New York show, to the Chicago show, to the L.A. show. A universal swing basically has to know what those differences are.

Ryssdal: And is it a thing where they’ll get a call on a Tuesday afternoon and say “you need to be in Chicago by curtain time tomorrow?”

Bassett: Yeah. We had a circumstance where we had somebody get injured, somebody was on vacation and somebody else was out for whatever reason in Los Angeles. And we called an actor, I think it was at 10 o’clock on a Friday night, to say — well, I called the actor to say, “How do you feel about having an adventure this weekend?” And this actor was so amazing that she just said, “Well, that’s the job isn’t it?” And I said, “That’s exactly right. It is the job. Get some sleep. We’re sending a car for you at 4 o’clock this morning, so be ready for a matinee in L.A. if you need to be.”

Ryssdal: This is a bigger-picture question, and not probably even remotely in your control, but is there a finite number of productions of this thing that you can see around the globe eventually?

Bassett: That is a good question. I don’t know what that is. It’s funny, I was just sitting at dinner with an incredible producer the other night, Cameron Mackintosh, he did “Les Miz.” He did a lot of them. Of course, you know who he is. But I, at one point, turned to him and said, “At the height of ‘Les Miz,’ how many productions did you have out?” And he said, “Sixteen.”

Ryssdal: Wow, that seems like a lot.

Bassett: It was a record at that moment. But he then turned to me and said, “I think Hamilton will have more.”

Ryssdal: Wow, your job would be a nightmare.

Bassett: Well, it depends on how you look at it.

Ryssdal: Well, yeah.

Bassett: I can’t complain, I can’t complain. I love my job.