Im not sure but I think he means cut them longer, that way you can try long chucks out, and then you can cut them down little by little and experiment with sizes. Correct me if im wrong though DWDS.
I think there is a DIY prochux guide, I couldnt find it though. I think their normal length is 12"? Do they come in 14"?
And I think they come from 1" to 5" rope length, so theres room to experiment in a DIY prochuck.
Cant wait to see a your swordchuck.
I dont know about durable, but it does help protect the wood from natural wear and tear(Not the abuse theyll be taking from the chucker

) Termites lol? Its lacquer thats used on Woodalls isnt it? I think so, anyways that feels very nice on my Woodalls so you may want to try that.
Anyways I hope this gives maybe teenie tiny shed of light to your project.
Take care,
Alex