Convoy C8 Extension DIY

Hey Everyone. I've done a deep dive on this forum. Most posts on this topic are old. Links to extension tubes are rotted. Searching for the tube on the referred vendor sites come up empty.

I did find a C8 extension tube on fastestbest. And did try to order it, but they charged my card, did not send a confirmation of order and would not respond to multiple requests to confirm my order. Fail.

So.

Looking for a DIY to create an extension tube for the Convoy C8. Simon no longer sells the piece. He also does not sell the L4 extension which may have worked.

I know there is an extension for the S2, however as the body of the C8 and the S2 extension are dual male ends, there is no way to connect the two without a female-female extension adapter which I haven't been able to find.

Has anyone found an extension tube from any other brand or seller that fits the threads for the Convoy C8 body? Or has anyone created an extension tube ground up? And if so, could explain how you did it, I'd be super grateful.

Thanks in advance!