Thanks for the detailed response - I agree that the old Linear workflow was easier and more reliable, but I find my renders look far better with the larger color space offered with aces.
I personally don't concern myself too much with the technical side of color as its way too big a concept, Im just trying to set up a solid workflow so I don't need to think too much about it from job to job. Its worked well up to this point but now with the changes suddenly the colors are all off although if anything its supposed to be easier now.
I'll get in touch with Maxon and see if there's anything they recommend, thanks again