I think the mouse movement being jumpy is a result of the game grabbing your mouse and forcing it to move to the center of the screen (or some other similar thing, games all do different stuff with the mouse and it's hard to account for).
RahiTuber directly translates your mouse's position on the screen into a position co-ordinate for the layer, so if the layer jitters, that means the mouse jitters. I'll try to add something to smooth any sudden jumps.