Don't get too excited about 8k monitors, 4k is already stretching it.
I bought a 4k monitor a couple of months ago, thought I'd be able to save on space (a single 4k monitor equals 4 regular monitors, right?). Turns out it doesn't. Since the monitor has a diagonal of 33", everything on the screen is a bit too small to read, and even though I have a fairly capable video card (an nvidia 980), it feels a bit slow. In the end, I switched to a screen mode of 3840x2160 (instead of the full 4096x2160) which helped a lot with the sluggishness, and modified the number of dots per inch such that everything seems a bit bigger again. Of course that implied that I couldn't have everything in view, so within a week I set aside my pride and added a screen again
Still, I'm happy with this setup. Screens on top of each-other, in rows so to speak are an ergonomic nightmare for me. No massage could remedy what that setup did to my neck and shoulders.