The aim is to transform them into head boys and youth ambassadors. And practices developed at the Naenae Boxing Academy are now being applied by similar youth organisations nationwide.
So Billy, any advice for job-seekers in 2016?
His response leaves me nonplussed, a bit like being the Karate Kid, hoping to learn kung fu secrets, only to be given a sponge and a line of cars to clean.
Billy doesn't do 10-tip monologues, but a collection of boxing stories and personal experiences did seem uplifting.
He has invested his life in boxing but now it's just a means to an end.
"And that's to make champion men -- we endeavour to get positive values across to the boys who come to us, to help them succeed in life."
Billy returns to the example of his late mentor Dick Dunn, a gifted trainer who during the 1960s coached him and several others to national boxing titles.
From a difficult home with alcoholic parents, Billy was exposed to Dunn's values, which included aiming high, maintaining sobriety and decency.
Dunn came down hard on bullying, swearing and anti-social behaviour, and so does Billy.
But there was always an undercurrent of compassion.
"On several occasions, when the boy I was fighting wasn't lucky enough to have learned the lessons Dick taught me, he'd say 'you're too fast for this boy. Don't go for his head; go for his stomach. Remember he's somebody's son too'."
Do we all need a mentor?
"Yes but don't be fooled, some potential mentors really don't have their crap together. It's vital to learn more about yourself [from an outside perspective]. So if you lack a mentor, talk to your family and friends. We're often blind to what's holding us back."
When seeking to better one's employment prospects, he regards writing down goals and having a plan as essential.
People are generally only too willing to help you progress in your career -- all you have to do is ask, he points out.
His proof of the principle: World boxing champions including Floyd Patterson, Joe Frazier and Muhammad Ali have signed a famous punching bag at his gym with messages of support.
"I wouldn't have achieved much in life without my colleagues, or the many who have offered to help us.
"But remember, not everyone will stick with you forever, people move on and when they do you let them go gracefully, with your blessing."
The job interview is important, but preparation for it should begin months ahead. Billy says: "Associating with people who are going places."
In order to be a good catch, he recommends avoiding negative people, attitudes and speech patterns.
Exercise, good nutrition, grooming and the learning of good manners are essential preparations. "Alcohol tends to dilute your powers".
But there's no replacement for confidence -- assuming the world is for you and not against you.
Each training session at his gym begins with boys shaking hands with and greeting coaches and colleagues.
"We must greet others in a warm, polite, but confident way. First impressions also rely on good clothes and grooming. There's no excuse, because this is possible even on a budget.
"There's nothing wrong with trawling the charity shops to add to your wardrobe. You may find a nice jacket your size that's only been worn once. Learn to use coat hangers and an iron and you'll always look well turned out."
In Billy's world all things are possible through perseverance.
"Work out for 10 minutes, have a shower, get dressed-up and go to it. Job hunting is a numbers game -- keep knocking on doors all day if necessary.
"Say, 'excuse me can I work for you for nothing? I can't stand not doing anything all day and I just want to be busy'. By the end of the day mate, you'll have 10 offers -- because somebody's bound to say, 'come along tomorrow'.
"It may not be the position you wanted but you have to get in the door first, because nobody deserves to be general manager from day one. But you'll get there -- just keep punching."
