"He knows me just about better than anyone on the planet. We're quite comfortable with telling each other what we need to hear. He's got his coaching licence and my dad's also just got his coaching licence. He's involved in the coaching circles now, too, so he's another option for me. I've been really fortunate to have a supportive family around me.
"It's just the way it worked out. I had a great first part of my career with Rik Ellis at Ringside boxing gym. He took me to a point where I could look after myself and keep developing. I've got a great base and am honest with myself. I have connections in America and the UK and they're options I often take leading up to competitions. I'm fortunate to have a good network abroad as well."
The family dynamic that David has placed his faith in wouldn't work for everyone. Brothers close in age tend to fight each other as children, and that was true of the Nyikas, who have two sisters, but that rivalry has turned into respect.
"He was probably one of the reasons why I started boxing because I wanted to beat him up," David said of Josh. "He forced me to be pretty tough when I was growing up. He'd make me fight his friends. I was raised in a pretty handy environment in terms of being the young scrapper in the family. He's always been someone I've looked up to - he's been my elder and an incredible athlete, too."
Josh, a welterweight, is a former national champion and won his first paid fight in Cambridge in May. He has also travelled the globe competing alongside David at world championships and Oceania Games, so not only knows the amateur boxing business, he knows the best and worst of his younger sibling.
After recovering from a back injury, David is fully fit again and his immediate goal is competing at the national championships in Christchurch early next month.
He said he feels comfortable committing as an amateur because of the funding he receives from High Performance Sport New Zealand and assistance from Boxing New Zealand - he travels to the national velodrome in Cambridge nearly every day to train and receive medical assistance - but that's not to say the decision was easy.
The threat boxing could be banned from the Olympics is a perennial story and there is no doubt failing to get to Rio after several questionable decisions went against him at qualifying tournaments was a low blow.
"There was a lot of uncertainty in the amateur boxing circles. It has been a pretty tough decision whether or not to turn professional. But I'm a stubborn dude and I'm taking my chances to chase my dream of an Olympic gold medal. That's the pinnacle of boxing - amateur or professional - so I want to stick at it.
"It probably dampened it, if anything," David said, when asked if the Rio disappointment lit a fire in him. "I feel like I belonged at the Olympics and so it was a kick in the butt but I guess that's where the truly great athletes are made - in those dark times - so I had to drag myself out of a pretty crappy spot and make the best of the situation.
"I've always said that qualifying for the Olympics is harder than actually competing at the Olympics. Once you're there, you've done the hard yards and you just have to perform. The qualification standard is incredibly high for us Kiwis. Not only do we need to be on top of Oceania, we also have to be in the top three of the Asia and Oceania group.
"From memory, I think there were five potential spots to qualify for the Olympics. But I know I deserve to be there and I know I have the means and skill and resilience to get there. I figure it's a once or twice or possibly three times in a lifetime opportunity, so I have to take it."
So after famously training in car parks around Hamilton before the Gold Coast following his split from his previous coach, he's now clocking up more than 1000km a week travelling to train and spar, and considers it a fair price to pay, although he acknowledges he is lucky to get the financial assistance he does.
"It's a pretty cut-throat industry in terms of funding. You have to be performing at the highest level to get that funding. I've put my neck on the line and I guess it's paid off to date."
