gf == Gram Force per Square Centimetre == g/cm²
So at least thats easily convertible to Pascals. Maybe when they say 'g' they mean the same thing.
now if its inches of mercury
then there is a conversion to Pascals so we can compare cutting force in g/cm² which seems like a very sane unit for this.
I'm going to try and add precision (in mm) and cutting force (in g/cm²) for all the models we have looked at so far.