30 fps is the lowest recommended frame rate. Much below here the scene doesn't seem to be in motion. TV movies and TV shows use 30 fps. Anything above 60 is very decent. To use time within c_move, you need to first determine the speed of motion. What I do is determine the angle to go in first, then figure out the horizontal speed and vertical speed (this involves using the cosine and sine functions), and finally move based on this speed.