Hey guys

I have a 7D + Sigma 8mm and was wondering what you thought would be a better option for vfx work (IBL), since im using the fisheye on a cropped sensor. The NN5 or the R1?
I've read suggestions to tilt up 5 degrees to cover the zenith better but obviously this means less coverage on the nadir.

I'm after something that is hopefully repeatable in PTGui and that I won't have to worry about too much when on set.
I really like the sound of both nodal ninja products, however i'm wondering what the least amount of pics I can take for time purposes. I wonder if 4 pics around at 5 degree up and then a 5th 90 degree down nadir?