Looking at the fact sheet about WTR here
https://www.immigration.govt.nz/new-...residence-visa, under the
NZ job offer heading, with it saying that the job must be full-time, I doubt that your split working between the NZ base and the off-shore one would meet the requirements. This is a question that hasn't cropped up on the threads before, so there's probably not anyone who can share experience with you. To be certain, you would need to ask INZ, but be aware that this isn't the kind of question that the ordinary front-desk people, or the telephone-answerers, could deal with - you'd need to insist on speaking to a supervisor who's someone trained to interpret the regulations, not just read what's on a page.
If you applied for residence under SMC, you would have the right to come and go as much as you wanted in the two years after receiving it (on the two years' travel conditions that come with residence). You would have to be careful to be in NZ at least half the time in each of the two years before you applied for PR, however (the 184-day requirement).