"In the end we used Sonny to create go forward, to give us quick ball or link and offload, so we feel we can still get the same out of these other guys, but we might be trying slightly different things to get the same result."
Rennie said it was exciting rather than daunting to be entering into the new championship as defending champions, after winning the club's first Super title.
"Twenty-four of these players were in the squad last year so they are well aware of the hard work it takes to be successful and they are all willing to replicate that sort of work ethic again."
He said his squad, that has eight new players for 2013, were well on their way into pre-season training, with the focus being mainly strength and conditioning.
"This is the advantage of this period when you don't have to worry about playing games on Saturdays, it's about sowing seeds and working hard.
"We worked bloody hard last year. We reckon we were the fittest in the competition and it clearly showed in the results in the end.
"We were still able to perform at our best late in games."
Rennie said they would be training right up until December 21, before players were released for a two-week Christmas break.
He said all players would be tested on their first day back from holiday, with incentives on offer for staying fit. "Guys who fall short in any areas get hammered for it."
Rennie will be returning home to Palmerston North during the Christmas break to spend time with his family and three boys, only one of whom plays rugby.