A jury unanimously found Rusterholz, 51, guilty of the murders of Angela Maree Hallam, 31, and Joshua Eric Newman, 21, after a seven-week trial in the Supreme Court in Launceston.

The couple's stabbed, burnt remains were found in a Pioneer Parade unit at Ravenswood on August 15, 2012.

Justice Robert Pearce, in jailing Rusterholz for 45 years with a non-parole period of 25 years, noted that Rusterholz subjected his victims to "gross indignity" and had no remorse.

Crown prosecutor John Ransom read some victim impact statements to the court while others were for Justice Pearce to read silently.

Hobart woman Tiffany Winter read her statement aloud, standing metres away from the man who killed Mr Newman, her high school sweetheart and the father of her then four-year-old son.

"Jai lost the trust and love he had for the world," Ms Winter read.

"He said many times that he wanted to go to heaven to be with his dad."

Ms Winter said that Jai had a rare, life-threatening disease and would soon receive a bone marrow transplant from the donor registry, an operation he might have had earlier if his father had been alive and was a match.

The statements from Ms Hallam's sisters, which Mr Ransom read to the court, said Ms Hallam was a good mother when she was there for her three children, planned to leave the drug world which her sisters disapproved of and was happy with her new boyfriend, Mr Newman.

Defence counsel Evan Hughes, in his sentencing submissions, said that Rusterholz had been married for about 18 years and was the father of eight children aged between three and 15.

Mr Hughes said that his client was bashed in prison in October 2014 when he was struck to the face and his jaw was broken in three places.

He said that Rusterholz now had wire and plates inside his jaw and had lost sensation, taste and feeling.