mathof2 I haven’t and you don’t need to either 😀
Just stick to the meaningful units.
GH & KH relate to scaling potential and alkalinity (KH) in the water, KH also affects perceived acidity in the coffee produced (more alkalinity/KH = less acidity).
TDS is anything in the water, organic & inorganic, much of which has little to no effect on what we are interested in.
Course completed. Look at it as ingredients rather than ‘science’.