nah - mathias disappeared somewhere off the tip of south america, on a fishing trawler never to be heard from again
He is/was a commercial fishing net designer.
And the only other person who ever made one wouldn't sell it to me either
He also made a compound sling and wouldn't sell me one.
Some people are just mean

The cord mathias used is fly fishing line. It's weighted so you can cast a fly further - not difficult to get hold of. Just a bugger to braid by all accounts.