Have fun taking notes, but it's not practical and useful in tennis to be able to see clearly so close. In tennis we don't play in the length of the ping pong table. We play in much longer distances. For sure we can see and know relatively well where the ball lands. That's how we know if our shot is in or out.
"Depending on the "improved stroke" ... you can actually introduce more contact challenges."
Not sure what you mean. When I said "improve" I really meant "improved" as in I have shaped my FH stroke not only much easier to execute but I also could crank up the pace and placement. I'm a result based person. Not just feels-based. It wouldn't be an improvement if I found more challenges.
I don't know if there's a vision technique to work on. Ages ago
@SystemicAnomaly posted something about cascading vision. I gave it good many tries but couldn't see any benefits or if I understood it correctly. I dropped it. Now I just look at the ball, track it but pay attention to other things that I said above. I rarely frame the ball.