i just measured and I sit exactly 35 inches from my monitor screen to my eyes, 27" 2560x1440.
i wonder what would be the perfect screen size and curve (or none) for that distance?
The perfect screen size is whatever you're comfy with.
PPI affects scaling and text clarity, ideally you want 96ppi because that's the correct actual size for content and it's 100% of the legacy printed media standard 96dpi that is older than you, me, and any kind of computer display ever made. Windows scaling is garbage so somewhere close to 96ppi is good for 100%, and somewhere close to 192ppi is good for 200%, use other values only if you have no choice, or if you're sitting at a very different distance to the intended "reading text sat at a desk" kind of distances.
Larger screens are akin to more screens, without the bezel interruption
People with multiple screens will universally tilt them to face themselves at their seated position without even thinking about it. In an office with several hundred people using dual or triple screens, not a single person has all their screens lined up straight.
My theory is that the ideal screen radius matches your sitting distance. This would however create some barrel distortion since curved screens are typically only curved in one axis, so the larger the discrepancy between vertical curve and horizontal curve, the worse an image looks. Given that we don't really have any dual-axis curved displays, I think the correct answer for "what's the best curve radius" is more complex but easy enough to explain:
You want the curvature to be as little as possible, whilst also ensuring that your viewing angles to the extreme edges of the display are within the gamma/brightness/contrast sweet spot of the display technology. Here's an RTINGS review of my Odyssey (VA) and you can see that colour saturation drops off a cliff at about 25-30° and brightness drops off a cliff beyond 15-20°
So for my particular display it's important that at my typical viewing distance the viewing angle of the far edges is no more than 20°. The 1000R seems to make that the case, but it seems like the edges are still almost perfectly square-on to me, so I could probably get away with a 2000R curve that would still keep the edges within the viewing-angle sweet-spot.