Now, if this curving light is responsible for the appearance of the sun "setting" phenomenon on a flat (but irregular) surface, then at an elevation above the obstructions of that surface, I should be able to intercept some rays that have gone past parallel to the earth and are now propagating along a path that would cause the sun to appear below the horizon.
Incorrect. Any light reflected off the Earth, which is what you would see as the horizon, curves in exactly the same manner. You cannot treat sunlight as curved and other light as straight and expect any conclusion other than nonsense.
The problem lies in this we are thinking about this as if each line from the sun is representing a stream of photons or a lazer like the video attached.
The problem with testing this is that sun does not emit light like the video shown below in one concentrated beam going in one direction. The sun emits light more like a light bulb.
I'm trying not to think of it like a laser. To understand what it would look like if seeing the light from the sun after it has curved upward, I use the analogy of an inferior mirage. In that case, you may still be seeing the source of light via a direct path, but you are also seeing light from a curved path that was directed downward and then, due to atmospheric effects, curves upward to the eye. As a result, you see the object(s) via their direct light path, but also see the mirage that is below the horizon.
My stand is (was) that, in the case of the sun, there is no direct path in EA at such an oblique angle. Instead, all you may intercept is the "mirage"-like upward curving light, which -- like a mirage -- presents the object to the view below the horizon.
But that is if only the un-reflected light of the sun is curved. If all reflected light curves too, then anything illuminated will also be displaced in the y-axis, including the surface of the earth and, ergo, the horizon. So even though the sun light might be upward curving, so is the light from the horizon. So, in effect, EA replaces the curve of the earth's surface with curved light, and that would allow an explanation for why a flat earth might suggest curvature, contrary to the more standard FE argument that there is no appearance of curvature and that arguments for such appearance are misinterpreting the observations.
I shake my head at the perspective and "convergence zone" and "obscuring waves" arguments for things like ships or skylines or celestial objects disappearing beyond the horizon. But this curved light theory is intriguing and challenging (if looking solely at earth-bound phenomenon and excluding beyond-earth evidence as suspect). It strikes me as a sort of similar to the luminiferous aether, as in something that is postulated to exist but to explain natural phenomenon, but not (yet) detectable. I suppose dark energy fits into that sort of category too.
Something I've mulling over is, because the sun isn't a point source of light, wouldn't the appearance of the sun become distorted the greater the angle away from vertical? Again, looking at the sun through atmospheric effects that are light "bendy," the sun does get squashed, terraced, mirrored, stretched, etc. when at a low angle of incidence to the atmosphere. If UA was curving the light of the sun, at close to horizontal to the x-axis, wouldn't the difference between the middle and its edges be bending differently, causing the sun to elongate or squish? Not just within a few degrees of the horizon, but from 10 or 20 degrees elevation, I'd think we'd start seeing something less than spherical.
No?