I've tracked this video (project file is attached).
First, I've setup an actor's model:
- aligned with T-pose on video (with Move tool), switching between cameras
- adjusted height so model's height looks like actor's in all cameras (after changing height, you need to move the model along Y axis to set bit back on the ground plane - this is not needed if proper actor's height is specified in New Project wizard)
- then run Analyze Appearance and eye-dropper for hands' color
- increased body mass index to compensate baggy clothes (while shooting mocap, better to wear a bit tighter clothes)
After that, the tracking went smooth till the segment around frame 180, where the right arm is close to the chest. At that moment, the tracking error occurred, because the arm was hardly distinguishable against the body. I've almost cleaned up this error by using
the recommended technique (manually edit the pose with IK/Rotate, then track backward), in several segments of 10-20 frames length. To avoid such errors, it is recommended to wear a short-sleeved shirt over differently-colored long sleeves, so that arms are clearly distinguished against the body.
There were no more problems till the end of the video, where you turn away from the cameras and they simply do not see the left arm.