And why not? He is that rara avis, an American theatre composer whose big-budget musical is opening on Broadway.
Well, for one thing, he's had to deal with a very public monthlong preview process in the glare of New York press coverage. Having played no out-of-town engagement, his Titanic has worked out its considerable technological kinks virtually in public.
Yeston is still clam, still cheerful. "This is no different from every preview process," he said. "Every show is a mess at its first preview. No one's had enough time to rehearse in costumes, traffic patterns backstage haven't been worked out, machinery weighing thousands of pounds is being operated for the first time. And, also, it's the first time all the material you've written is before the public. You don't know if they'll laugh at every joke, cry at every moment of pathos . . ."
Yeston is reminded that in Moss Hart's autobiography "Act One," Hart learns from veteran playwright George S. Kaufman that playwriting consists of two parts: writing -- and cutting.
"I would augment that," Yeston said. "There's writing, cutting and rewriting. Over three or four weeks we've perfected the piece, removing what doesn't work, replacing what will work. You must get it across the footlights to the people in the audience. And the only way to learn if you've done that is in real time, in front of a live audience."
During previews, as the technical team worked to make the special effects operate correctly (they were working without visible problem as of the April 19 matinee), Yeston was doing that cutting and rewriting. Among cuts: songs for a young couple in Act I; a number for the doomed millionaires in Act II.
"This kind of thing has been going on since Aeschylus," Yeston said. "I'm sure he cut a scene from Oedipus. Every show that tries-out out of town goes through this. But if you're a show called Titanic, the irony of the process is just too tempting for the popular press. 'They hit an iceberg on the first preview.' But we expected that."
Yeston and librettist Peter Stone "froze" the show Thursday, April 17 so the actors would have time to learn the show, as it was, in time for opening night without worrying about more changes. Also, the first critic preview was scheduled for Friday, April 18, and New York Times critic Ben Brantley was scheduled to see the show that night.
Did that faze Yeston?
"Just wait," he said, confidently.
Yeston spent the morning of April 23 quietly, preparing his opening-night gifts to the cast -- a sweatshirt reading "I survived Titanic with the show's logo. Musicians in the pit will get bottles of champagne. Yeston will leave these in the dressing rooms this afternoon so the performers will find them as the come in.
As for opening night, backers and creators of a Broadway musical fall into two general categories: sitters and pacers. And it has nothing to do with experience. Some of the most grizzled of old veterans still pace. Richard Rodgers was an epic pacer.
"I am usually a pacer," Yeston says. "I go to the balcony to check the sight lines way up there, to check the sound system to see how the balance is. I typically visit the guys who run the sound board, then I go out and come in through the stage door and visit the [orchestra] pit. Sometimes I look out and see the faces of the people in the audience."
The opening of Titanic will be different, he swears: "I plan to sit in a seat with my family. It will be the first time I will have sat through the entire show."