Did you check how it affects flight time and maximum speed (or wind resistance)?
I'd be more interested in how it effects stability for shooting video. In the video, it looked like the added weight was causing some instability (rocking) in stopping, starting and turning. Don't know if the gimbal can compensate. Do you have footage from the Mavik?
Video is stable and smooth , did not try "Sports-mode", but it´s not necessary....
The "balls" weight is less then the Prop-Cage, flighttime with balls is about 19min....
Prop-rpm hovering: 6100
Did not try on a windy day!