I'm looking for a colorspace converter, found one but it's not performing the said tasks, I'll keep working on it. I can't even post an excel, recently upgraded my computers and they don't even have the basic work spreadsheet on them anymore, what a rip!
I only got close to the lens when measuring contrast ratio, all other measurements the meter faced the HP screen. I've performed dozens of measures and the results of blue are always consistant which provides me some faith it's capable of, at the very, reading the light level. I've noticed anything about 1 cd/m2 the cut-off for faithfull repeatability, the 75% blues always fall above that. Full resolution CIE charts show the errors between red green and blue about equal visually, I suppose if the filter is moving the primaries non-relative to each other this may be causing the error in secondaries as it's not as JVC intended. Since the JVC does not have a blue screen mode I'm using filters to adjust the color decoder which as you is not the most accurate method but all three colors (utilizing the squint method) look bang on, better than I've ever witnessed.
I'll do my best to covert xyY to LCH but not right now, all this typing is cutting into my drinking time and that's something I'll never get back.