This is an example of using Rewind Debugger to time root motion animations. In a frame I have the hand dropping below the mesh when she's climbing up.
1) First Copy what ever you need for testing to a new clean level.
2) Open the animation you want to edit, under Edit In Sequencer click Edit with FK Control Rig
This will automatically create a level sequence and open it at origin. The animation must stay at origin. Do not move it.
3) Drop your player character into the scene. Choose to auto possess player 0
4) Open Rewind Debugger tabs. Use the eye dropper to select your player character.
5) Hit Play
6) Press Shift F1 to release the mouse and hit record in Rewind Debugger.
7) Execute animation
8) Press Shift F1 to release the mouse and PAUSE the game. Now you can rewatch what Rewind Debugger has recorded.
Rinse and repeat until happy.