Jumpers - how long is long enough

This question relates to the jumpers found on speakers with Bi-wire terminals

Most people agree that most of the jumpers provided should be replaced.

But how long should the new jumpers be?

A fellow audiophile who has spent some time investigating this recommends at least 50 cm
- he also recommends the neutral be of a larger gauge and 70cm in length

I have no reason to doubt his observations, because he is extremely thorough with his research and I have also found his observations to be beneficial..

I was just wondering if anyone else had similar findings they would like to share on this topic

Regards - Steve