Sadly, I had to return my OF120 in the end, after a number of problems over three machines including focus, mechanical noise and the dreaded colour banding problem.
I have since "re-acquired" a Canon FS4000US, the scanner I had previously. I decided to do a qualitative experiment, comparing a scan of the same negative on the FS4000US to a scan of the same image on the OF120.
I used Vuescan for both, scanned as RAW file image, no other corrections in Vuescan, inverted in ColorPerfect, then applying the same type of correction curves to both images. The OF120 scan was downsampled to 4000ppi.
As expected, because I scanned as an 'image' (rather than transparency), I had to apply the most correction to the blue channel, then green, then red for the FS4000US . However, the OF120 required far less blue correction - in fact, the amount was similar to green.
What I didn't expect to find was the totally different way in which the two scanners render blue. The FS4000US scan is closer to the look of the sky when I took this photograph, and all three OF120 machines rendered the colours in the same way.
Now, as I say, this was a qualitative test, and the film was expired Orwo NC3 movie film. But, I am sure I have read that it's the blue channel that's the cause of the banding problem, so how that ties into these tests (if in any way) I don't know.
I'm very happy with the FS4000US, but unfortunately I don't now have a medium format scanning solution 🙁