In the "old days", I did something similar for learning exposure and lighting ratios for shooting color negative film. Using movie film in a still camera I exposed frames of a white towel from - 5 stops to + 6 stops using a light meter and printed the results on color print film. Placing the frames, in order from dark to light, on a light table I was able to visualize the effect effect of the exposure (assuming "standard" printing lights) on the resulting film print. I found this very helpful to understand what my spot meter was reading.
But, film processing and printing were standardized by the film manufacturer and we could only print to the gamma curve designed by the manufacturer. Basically, a zone system, pre-viz for movie film.
Today, there is no standard gamma for our final products. All of this can, and is changed and adjusted during computer color correction. There is no standard.
You are using your in-camera REC709 LUT as a standard. But, it is important to realize that there is no "Standard" REC709 LUT. Each camera is different, and many cinematographers use non-standard or customized viewing LUTs as well.
So, I think you might be throwing yourself down a rabbit hole here. You will do a lot of work learning this one particular camera and LUT. And the final product may be changed to look nothing like the preview (if you choose). And your work will not apply to any other camera or viewing LUT. There are just too many variables here.
My best advice, from my experience, is to not use "false colors" in the viewfinder and to just make preliminary judgements about lighting from a good on-set image display. If you can toggle the LUT on/off to see the full LOG image exposure, that can keep you out of trouble, but basically judge the lighting by the REC709 LUT from your camera on the viewing monitor.
To really learn your camera capabilities, I think it's far more useful to view your LOG exposures in a color correction software and do basic color correction on them to see how the exposure is working to give you the final result that you like. So, instead of making "false color" graphs, play more with color correction to learn your camera and exposure.
When I'm shooting, everyday I go home with a copy of the day's work on a little USB3 hard drive. I take the LOG footage and select shots that I'm interested in and color correct them to something that approaches what I had in mind on set. Doing this, I learn how far I can stress the camera exposure and still get what I want out of the image. It's not very time consuming as I'm not watching and correcting all the dalies, just selected takes.
You can even do this with selected frames in Photoshop if your more familiar with that software than something like Davinci or Speed Grade. On my MacBook Pro, with calibrated (ish) REC709 screen I usually use Speed Grade for this task as it's less demanding on the computer than Resolve. I also watch the video scopes carefully as well.
So, because the REC709 viewing color space is standardized, but the viewing LUT's are not, I think your attempt at a "false color" zone system is admirable, but, unfortunately, will not be very helpful in the end.
But, if you really want to learn a lot of stuff, keep at it until you see why it's not so easy to visualize your results this way. A lot of the best education here is by trial and error. And, maybe, who knows, you'll stumble upon a system that works really well for you. Good luck!