I remember when a friend got a plasma TV and connected to their computer for some Battlefield 2. He had to stop playing that way because he got motion sick from having an image the size of a wall whipping his view around. Good luck!
For TV viewing, you want between a 20-40 degree viewing angle. I'm sure the recommendation is quite a bit larger for computer use. It's quite a large range, but any way you cut it sitting in front of a TV is not it.
A 43” is basically a 2*2 grid of 21.5” 1080p displays without bezels. It’s not particularly wide, two average 22-23” 1080p monitors and it’s taking up much more space horizontally. With a deep enough desk, the added verticality isn’t particularly bad either.
It's a 2x2 grid of 37" 4K monitors, or a 4x4 grid of 18.5" 1080p displays. It would be more productive if the desk were 3-4" further away and the monitor were 4" below the desk instead of 1.5" above it, as the top 10" or so is impractical to use while sitting except as a status area. OTOH, I welded up the custom mount to my lifting desk, so I can stand and raise the desk so that the keyboard is on the actual desk instead of the tray. In that configuration it maximizes my usability of the screen.
A plasma would be like sitting in front of a heat lamp. My old plasma make me have to put a booster fan on the duct to that room. I do have to be careful when zooming and panning; the family was scoping out Aberdeen, Scotland last night via Google Earth and I had to be a good bit slower on the controls.