Being one of the three 2012 Emerging Artists with New Zealand Opera has also been invaluable.
Not only did this give Rayner an opportunity to play two small roles in this year's Madame Butterfly, but it has been "a chance to be a fulltime opera singer in New Zealand at a young age, even if only for a couple of months at a time over a year and a half," he says. "It helped confirm for me that this was really what I wanted to do."
Rayner has enjoyed the collegiality of his fellow emerging artists, Bianca Andrew and Edward Laurenson, and was thrilled to understudy Jonathan Lemalu's Leporello when the company staged Don Giovanni in Christchurch this year.
"It was inspirational. You learn so much from such consummate performers, especially when they're New Zealanders with overseas experience who have been invited back."
While in Britain, Rayner seized the opportunity to take consultation lessons with carefully chosen teachers - back home, he studies mainly with Margaret Medlyn, with occasional input from Richard Greager and Jenny Wollerman.
"I like having different people's input," he says. "It's also a useful experience in terms of my own self-knowledge to be able to collate all the different comments that I get."
Being a singer has always been a bit of a waiting game and voices must be carefully tended. "I am not likely to yell myself hoarse right before I go on to do a concert, or try to sing a Wagner role when I'm 24," he says. "The main issue with the voice is not to try things that are too big for you too early. That's a trap for young baritones, wanting to sound older and bigger than they are. You hear these wonderful singers like Bryn Terfel and want to be like them, but you can't yet, and it can be so frustrating."
For the moment he is happy with his favourite composer, Mozart.
"He writes the sort of baritone roles I can sing now, whereas most other baritone roles are for older voices."
As with so many of his singing friends and colleagues, oratorio has been a major source of both employment and enjoyment. Already this year he has sung in Beethoven's Missa Solemnis with Wellington's Orpheus Choir and Haydn's The Creation with the Hamilton Civic Choir.
"Oratorio allows more focus on the pure music of it," Rayner says, while pointing out that these choral works have just as much character and drama as their operatic equivalent. "It's not like you can just stand there and sing this glorious music by Bach or Handel, and that's it."
He is eager to pick his favourite aria in tomorrow's Christmas Oratorio and chooses Grosser Herr, o starker Konig.
"It comes with a brilliant trumpet obbligato and is so joyous in a particularly wonderful baroque way.
"It's like you're doing a duet in the middle of all that orchestral sound, and it's oratorio that allows you that kind of interplay."
Performance
What: Bach Musica, Christmas Oratorio
Where and when: Auckland Town Hall, tomorrow at 5pm
