The Drive M7 Aspar team rider briefly rode the 2015 machine at last November's Valencia test.
"At Valencia we got in some decent laps to give us a little direction and data," Hayden said at Sepang on Tuesday.
"But really we've got a full schedule to get through here, especially electronics. We can use some of last year's settings as a little bit of a reference but now we have different RPM, gearing… a lot of stuff. We'll be starting fresh," he added.
The 'RS' replaces last year's underpowered RCV1000R Production Racer. Although the RS must run the standard ECU and does not have a seamless gearbox, it is powered by last year's title-winning RC213V engine and has the benefit of the Open class tyre and race fuel concessions.
The Aspar team are happy with the new bikes, powered by last year's title-winning RC213V engine, which they believe will give them 'a chance to fight'.
"In Valencia already, even on that little straight, we were 15km/h faster," Hayden said. "So that's a good step. We'll see here, with the bigger track, where we stack up and where we're at.
"We're going to need [the horsepower] because it's a really competitive field this year. There have always been good riders here in MotoGP, but as far as the bikes, everybody has got pretty good stuff this year," he added.
Hayden and new team-mate Eugene Laverty will take to the track alongside their 2015 rivals for the start of testing on Wednesday.