Tarapata's partner and mother of his three children Tamara Cassie worked at Ezy Cash with the victims and was at the premises on July 19 last year.
Minutes after dropping her off, the defendant walked through the store into the lunch room where he slit Mr Matthews' throat and stabbed him 15 times before stabbing Mr Fanning six times.
Both bled to death on the floor as Tarapata fled in the car with his partner and their kids.
He was found later that night near his family's home in Huntly.
"Part of the real tragedy is just how senseless and unprovoked these killings were," Crown prosecutor Josh Shaw said.
"Mr Matthews and Mr Fanning had done nothing to invite the attention or anger of Mr Tarapata. To the contrary, there is some information before the court that suggests they had always been generous to Ms Cassie and her family."
Tarapata had provided letters of remorse to families of the victims but Mr Shaw said they were reluctant to accept the "bitter pill".
Mr Matthews' sister Julia Matiu said her brother was a "gentle giant" and the thought of him calling for help had been a huge burden on her.
"The fact he's no longer in the world has left a massive gap . . . a good guy taken way too soon," she said.
Ms Matiu and two other sisters also directed comments at Tarapata who sat in the dock with his head down throughout.
"I hope you can understand my pain and that of my family. Maybe you could've just asked for help instead of taking someone's life for the sake of your own," she said.
"I feel sorry for your children. So many lives have been destroyed by the acts of one man."
Mr Fanning's daughter Jenny Squire described her dad as "a bit gruff" but always generous when someone needed help.
"I live with the trauma of what happened. The images and information I can never un-hear and never un-see," she told the court.
Tarapata's lawyer Bruce Hesketh said his client was psychotic at the time and his mental health should be at the forefront of the court's considerations.
The defendant, who was diagnosed with schizophrenia, could still not fully comprehend what had happened, he said.
Despite allowing the photographs of Tarapata to be taken at sentencing, Justice Andrews reversed her decision at the last minute this morning.
She reduced his sentence for his mental-health issues and "sincere remorse" and imposed a minimum period of imprisonment of 17 years, before he will be eligible for parole.
Outside Emmett Fanning read a statement on behalf of both families in which he said they were happy with the outcome of sentencing.
"He has finally been held accountable for his brutal actions," he said.
"The last year has been horrendous for us all."
Mr Fanning thanked police and victim support for their help and members of both families shared warm embraces before they went their separate ways.
