Harris and Manson showed a strong run of form while touring Europe and will hope they have put in enough work to test the Sinkovics at the Rio Olympics.
In the women's pair final, Union BC's Rebecca Scown and partner Genevieve Behrent were joined by the Kiwi backup pair Olivia Loe and Holly Greenslade.
Similar to the double sculls, Scown and Behrent worked their way up from fourth at 500m but could not peg back the Great Britain team of Helen Glover and Heather Stanning, as the Olympic champions won by just under 2s in 6m 52.79s.
Scown then climbed into the women's eight boat for their race, alongside AWRC's Kerri Gowler, with the Kiwis racing Great Britain and the Netherlands in a straight final, where the United States were notable by their absence.
It was easy gold for the New Zealand eight as they led from the 1000m mark onwards and were 2s ahead of the British, giving Scown gold and silver from her weekend's work.
In the other events, there were no surprises in the men's pair as Hamish Bond and Eric Murray finished more than a length ahead of Australia's Spencer Turrin and Alexander Lloyd.
The lightweight men's four combination of James Hunter, Alistair Bond, reserve Matt Dunham and James Lassche also backed up their earlier world cup gold medal with another resounding victory.
In the men's single sculls, Olympic Champion Mahe Drysdale claimed gold over European champion Damir Martin of Croatia.
Zoe McBride had won the lightweight women's single sculls earlier in the weekend.
