Let BretFX Smooth Strobe do the math for you! Use the judder-free, frame rate specific versions of BretFX Smooth Strobe for a smooth cadence in your strobed video every time.
BretFX Smooth Strobe stutters the movement of video by skipping and repeating frames, while keeping the speed and timing of the video clip in tact. It includes 4 effects. 1 custom strobe effect to dial in any frame rate (smooth cadence or not) from 1 to 60fps. And 3 others designed specifically to limit your choices in 24p, 30p and 60p sequences to frame rates that will reproduce a smooth cadence.
Final Cut Pro X 10.2.3+
Download includes the BretFX Smooth Strobe set of 4 plugins and instructions.