OK, thank you, then we don’t need the Python hacks. 
Do you agree with standardising on using percentages?
I think the following would make sense:
- Look:
- offset: since black and white display target are set in %
- slope (maybe): it’s basically a multipler, so a plain number is OK, but maybe a slope of 120% looks better than 1.2. Contrast-like values are in plain decimal multipliers in sigmoid and filmic, but in color balance rgb contrast is a 0-based percentage (a modification), and so is gain on the 4 ways tab.
- power: keep as a number
- saturation: as percentage
- preserve hue: as percentage
- Curve params:
- basic:
- pivot x shift, pivot y linear: as percentage (ratio of the distance to shift the x coordinate towards the left/right edge). Also, probably better names? ‘pivot input brightness shift’ / ‘pivot input shift’, ‘pivot output brightness’ / ‘pivot output’?
- contrast around the pivot: a plain number; keep, as that’s how filmic and sigmoid use it
- toe/shoulder power: keep
- advanced: already uses % values, except for gamma; gamma is just a plain number, keep
- basic:
- Primaries: already uses % values for insets, degrees for rotations