The day Metro sat in on rehearsals, the ensemble worked for most of the day on Oom-Pah-Pah - a rowdy, hectic tavern number, which by 4pm had most of them exhausted ... and then they ran through it again.
Elements of some scenes have set choreography, but others are workshopped so that the cast can create the mood and movements themselves.
It's all in line with the template set in place by Matthew Bourne, who created the choreography for Cameron Mackintosh's revival production in 1994, directed by Sam Mendes, which ran for a record three years at the London Palladium.
Most of the directors of music and text for the Sydney production have been with the show since 1994. Gill has been a director with Mackintosh since the 1980s, while the choreographer for Sydney, Geoff Garratt, was dance captain and assistant to Bourne for the original production, but found the latter role so tough that he eventually opted out of performances. This is partly because Garratt was, and still is, in charge of the kids - from their dance routines to their behaviour onstage. There are two separate child casts, which means he deals with 20 bouncy and talented children aged seven to 15 every day.
He says the trick in working with the kids is "to build up their trust and confidence. It's creating an atmosphere that they can work in, but not being so loose that you don't get the work done and they're undisciplined."
Thirteen-year-old Matthew Waters, who is one of two Artful Dodgers and a veteran of such shows as The Boy from Oz, makes it clear the children hang on Garratt's every word.
"Geoff is just amazing with what he can do," he says. "He can think up a whole dance routine in about five minutes."
Keegan Joyce, one of the boys playing Oliver, is well aware of the massive workload he is facing - first year of high school, sport and a big role on the professional stage. With a poise beyond his years, he quotes the saying "If you want to get a job done, ask a busy man to do it for you". A busy man? He grins: "Well, I'm a busy boy."
Joyce was encouraged to audition for Oliver! by fellow cast members from an amateur production of The Secret Garden, and with no dance or drama background won the title role. He admits he's still "amazed" but is now focusing on his greatest challenge: being the character, rather than just playing it.
"You're not the actor Keegan Joyce playing Oliver Twist, you're Oliver Twist being Oliver Twist ... that's the hard part," he says.
Off in a smaller rehearsal room, stage veteran John Waters is under Gill's watchful eye, wheedling and scheming his way through one of the show's best songs, Reviewing the Situation. As Fagin, the comic baddie of the piece, Waters gets to be deliciously seedy.
He muses during a break that he was delighted when asked to audition for Fagin, as here was someone who could never, under any circumstances, be considered suave.
"Fagin is a character role which, when I think about it, I am perfectly suited for," he says with a smile. "For me the acting part is playing those sophisticated types, because it's not me. It's something I can adapt to, and have made my living at from time to time, but now's the time for a bit more of a laugh."
The character created by Ron Moody in the 1968 film of the musical has become almost as classic as the film itself. Waters is aware there will be some in the audience who will come expecting to see Waters as Moody, but he's not about to gratify such wishes.
"I want to be the sort of Fagin that people want to see, but at the same time do it my way ... but you want to be the definitive Fagin for each audience member. That's what live theatre is all about."
The clock ticks around to 5.30pm. Most of the adult cast have gone home, but not Tamsin Carroll, who's playing Nancy - the ultimate tart with a heart - who's in love with the brutish Bill Sikes (Steve Bastoni). Carroll has been here since 10am, sung her lungs out through the afternoon in Oom-Pah-Pah, and will be here until 8pm working on a scene with the kids.
She's tired, but devoted. She even admits to crying the previous weekend - the first time she saw the "gang" of young lads troop onto the stage - "because it's just such a beautiful show ... the children are so hard-working".
That Oliver! could have this kind of impact on someone in the production speaks volumes about the musical's capacity to charm. This kind of longevity is rare, and Gill puts it down to the melodies: "Everybody knows these tunes."
Waters agrees that the songs are "extremely catchy", but believes it's more because they are so good at telling the story - and the story, for him, is the thing.
"I rather like the fact that this is a musical about an extraordinarily black scenario," he says. "It's tragic. This boy [Oliver] is hideously treated, Bill Sikes bludgeons his poor girlfriend to death and then dies in the end. It is pretty black. But there's hope shining through the blackness."
Director: Graham Gill
Stars: John Waters, Tasmin Carroll, Steve Bastoni, Mark Mitchell, Stuart Wagstaff, Philip Dodd, Keegan Joyce
Where: Lyric Theatre, Star City, Darling Harbour
When: Previews until Wednesday, season from Thursday until June 16
How much: $33-$78 plus booking fee
Bookings: 9266 4800