I usually shoot and render in 1080p 60fps. However, I was recently experimenting with 720p 120fps on my older Sony AS100V "Action Cam".
I rendered it at 720p 30fps (default Internet HD 720P) to see how it would look. It makes for a very nice slow motion. Then I experimented with custom output driving it to 59.94 fps. It was still at slow speed and, surprisingly to me, the result was worse. I played the two side-by-side and the first render at 30fps was "sharper".
Ultimately what I want to do is render most of it to appear at "regular" speed, but slow down parts of it using "Velocity Envelopes". I've experimented with various ways to do that with varying degrees of success.
To cut through hours of experimentation, what is the logical way to approach this goal? What custom render settings should I use?