If you’re not willing to move your seating for a simple/short (2 hr) movie test, then my perspective is that your viewing angle will only increase from 15.9º to 18.26º not so much that you’ll notice a decent enough impact to warrant the cost of the new 58”.
I fail to see what the viewing
angle will have to do with anything here; I will be at the same angle, I'll just be bringing the screen size up eight inches...
Now, your sentiment is that this
will not be warranted as far as an upgrade? The first time I brought this issue up in a totally different thread, the opinions leaned towards the fact that even a "mere" eight inches will yield a difference in impact...