Here's a suggestion that takes an opposite tack from the OP, that is, to give a historical oversight rather than look only for the ultimate NTSC quality:
I recently bought a collection of Johnny Carson highlights; not sure if it's the same one the OP mentioned:
https://smile.amazon.com/dp/B000068W...roduct_details
Disclaimer: I have only watched the first disc so far.
The first clips are early black and white and kinescopes, and then they progress into color, with the quality improving as you go. (There is one color clip that looks to me like a color kine.) The constant plus to all of this is that the shot framing from back then is cautious so that everything important fits in the roundy screen, but is usually as close as possible within that constraint to squeeze the most out of NTSC's limited resolution.
I think this makes for an excellent quick demo to non-collectors and younger folk of what TV could look like in the days of the roundies, good and not so good, as you skip through the years.