Yep, that is indeed my mold design. It works well with flexible material, it does not work well with rigid epoxy unless you coat it with mold release. I found this out the hard way.
If anyone needs different cable diameters for either end, let me know and I can upload different ones. The ones there right now are an 8mm to 10mm and an 8mm to 8mm if I remember right.
I do occasionally 3d print things for clients, message me if you would like one printed and we can figure out a cost. it’s about 1/2lb of plastic ($18) and around 2 hours machine time and 1 hour labor (trip to post office and back, setup, etc) so it’s generally not too horrible.