"We had been swapping a lot of things on the suspension but, obviously, we have found the right settings," Kreutz said. "I tried very hard at Hampton Downs but we had problems in the wet getting the correct set-up.
"I've recently changed tyres brands, so we were still learning things, plus it was wet for one race and then dry for the next.
"I actually had a terrible start in [Sunday's] second race. I was about ninth spot on the grid and had to fight through a bit of traffic."
Kreutz said he and his fellow German travelling and racing companion, Dresden's Steve Mizera, have been enjoying their stint here - his second trip to these shores while it is Mizera's first.
"It's something like minus five degrees and snowing in Germany at the moment. We're avoiding the winter and enjoying the summer conditions here very much."
Both men will remain in New Zealand to tackle the four-round national superbike championships, which kick off in Christchurch on January 5.
Mizera finished ninth and 10th at Hampton Downs then 10th, ninth at Manfeild to be eighth in the standings.