Well, I like to see students demonstrate with hard chuks in their grading videos. Basically, you need at least two pairs of nunchakus in your arsenal. One soft nunchaku/padded designed for sparring and combat practice. One hard nunchaku, possibly made of rattan or bamboo; or a metal nunchaku with a shorter chain, like I use in the videos.
The padded chuks are also very helpful in the beginning stage, so that you do not hurt yourself. You can train fast and hard, while perfecting your technique. The around the neck, for example, can be dangerous with heavy chuks, as you can hit yourself in the back of the head. And don’t even get me started on hitting yourself on the around the neck part 2… – ;O.
In the grading videos, you want to demonstrate the kata with crisp control, precise execution, and realistic weighted weaponry control. This means that a hard chuk is the correct choice in the examination. Then, once you move to double chuks, you can get a 2nd pair of your hard chuk. Or, upgrade altogether to something different.