Three things typically determine bait distance behind the ball when downrigging.
The fish, depth of the ball, and the water clarity.
Wary fish, such as walleye and "some" trout, are scared off by the boat, so longer leads will help.
Similarly, if the ball is only a short distance behind the baot, we lengthen the leads also.
Below 50' we typically tighten leads up, and it really helps turning as Geoff stated.
Clear waters allow fish to see to see further, and the boat, so lengthening the leads works here too.
BTW, it's not only seeing the boat, but hearing it too that will scare away the fish (or attract them as happens often with coho).
I like Chamberlains and Blacks, but rubber bands are simple and also very effective when pinning your stacker where you want it.