I did some research on TV screen size vs viewing distance for the basement TV. I even cut out a piece of cardboard the size of a 65" TV and taped it to the wall with blue painters tape. 65" was supposedly the "right size" but we went up to 75" and I'm glad we did. The suggested screen height on the wall was also lower than I liked so I moved it up about one foot.
We sit about 13-feet back from the 75" screen and for us it seems just right. The screen is large but not so large that we have to move our heads or eyes back and forth to follow the action. It's up a little higher than recommended but not so high that we're looking up. Speaking for myself I kind of slouch back in the sofa with my head resting on the back cushion so my slouch position is looking slightly upward anyway.
Have fun searching for that perfect TV! Once you buy it the newer model will out next year :-)
P.S. 4K content is here in streaming movies and some live broadcasts but I don't know of any 8K content. Maybe it exists but who knows.
