Here’s an eBay guy making +0 extensions:
https://www.ebay.com/itm/P30sk-VP9sk...-/301961411963
I may have one each of X Grips (15/13) kicking around somewhere. If I do, I’d be happy to send them to you gratis. Just let me know. I should get my hands on them tomorrow if they are where I think they are.