You need a third axis on your chart (3D). Different props have different airfoils and different loads even if you hold diameter and pitch constant. Chart should work reasonably well if you only use one brand of prop and their airfoils are consistent across the all the sizes (not true for APC).

Thanks for the update on the chart. I think I'll stick with my method and let the plane and engine decide what is best.If you really want to know how props differ from make to make and batch to batch from the same maker. Make a pitch gage along with measuring width, thickness and end to end. Heck thats a science in itself.Even moisture content enters into it when the props are made. I mean if one wants to get critical. Now a days most of the named makers have better quality control. I am only writing about wood props. Cannot comment on composite nor do I have any reason to use any,I like wood. I don't use a computer radio either. From what I've seen going to various events most of the pilots don't fly any better no matter if they used wood or composite. Now maybe the fellows that are sponsored pilots might require composite, end result is whatever works.

The main advantage of composite props is that they are usually quieter than wood props - and they don't compress at the hub when mounting. The prop bolts stay tight on a composite prop, not on a wood prop.

Diablo-RCU, I will agree on the compression factor. As for composites being quieter than wood I don't have any experience of being able to compare wood against composite on a test stand or some other method.
I'd be interested in testing if some one would care to donate some props to be returned after the testing.
I currently test my engines 30"over concrete and measure the noise levels in a 360 degree circle with digital and analog meters.
FWIW

You probably won't test much difference on the ground - composite vs. wood. But, in sizes around 26 inch and larger diameter, when they unload in the air, the differences will be quite dramatic.

Diablo-rcu, with my limited experience. When a prop unloads it is a sign of improper throttle mangement and not having the correct prop which then is ineffecient.
A friend of mine has a 21x10 Menz S on a Taurus 3.2 and I've seen him fly his plane, do a loop carrying full power through out the entire loop and never heard the prop unload. The sound of the engine and prop never changed. I thought that was quite interesting. But I have heard other props unload so I know what it sounds like.I'm sure a stiffer blade is more efficient. And that may be the composites. I don't have an engine large enough for a 26" prop, not yet.