Was writing a reply but now I see that magically deleted it.
That's my point, Oaktown: Content leads.
I have a different aproach to speed variations, because I think flow is tied to motion blur, not to framerate itself (isn't that a video camera use legacy?). My starting point use to be settle what flow need the particular content.
Is still hard to explain me in a foreign language, but try to follow me.
If need a stacatto I can have it any framerate. But if I need a smooth slow down, I will center my attention on the motion blur. When creating content (like in c4d) we use to render an image sequence that's not tied to framerate (I know if you set a higher framerate at render will create more frames, but again, that's a metaphor). Then you render your image sequence as movie clip at any framerate. So, that sequence bundled on a 120fps clip at 1x will look same as 30fps playing at 4x, because frames are the same.
I want your toughs about this matter, please.