OK. A new method. This one works a bit better than the last one.
It requires for a full 360 degree spherical panorama 26 renders, but for my uses I just want sky, so 17 renders.
Full OpenEXR / HDRI Output.
Accurate distortions at the poles.
And it is automatable to a degree.
It still uses 3DS Max for OpenEXR stitching.
I will put together a tut if anyone is interested?
Check the attached image for the results.