Call RBS and get an opinion from them directly if you can. I'd also talk to North, they might still have that sail in their design computer if you have enough info for them to look it up, they would have all the information about the original batten design.
Is the sail full batten or partial?
I'd still go with RBS tapered battens no matter what, they produce a much better sail shape, and will actually allow your sail to hold its shape for a longer life. HOWEVER, if the sail has already lost
its shape (not sure how many hours are on it), then it may not be worth it..