With film transfer in mind, has anyone tested for optimum, smoothest, shutter speed in 24P mode - for objects moving across the frame (of a locked off camera.) 1/48th? My guess would be that faster speeds would be a trade off in smoothness due to the dead time between frames which I see as inducing a stutter in motion, as opposed to the smoother but more image blurred slower speed of 1/48.
Sorry I don't have the camera yet or I'd be testing this minute.
Any thoughts?

Film cameras operate at a wide variety of shutter speeds. Some have shutters of 1/43 of a second, some at 1/50th, some at 1/60th or even faster.

1/48 corresponds to a shutter angle of 180 degrees, and is a fairly common film shutter speed. But you can use slower or faster and as long as you're shooting 24P, it'll still look filmish, just with a different shutter speed.

Your summation is generally correct: longer shutter speeds = more motion blur, less strobing, and more light sensitivity. Shorter shutter speeds = sharper footage, more strobing, and less light sensitivity.