Nice job. I am curious about the transition in the middle?
That's odd. I replied hours ago. Even included a photo, but it's not here.
What I said:
I'm just using a piece of clear plastic tubing from Home Depot. The two mic cables fit very tightly through an inch or so of the tubing. Heat shrink over that. I've not seen it done this way before, but I didn't like "cable pants" or just heat shrink alone with the two cables stretching the mouth of it. This is nice and secure.
The tubing comes in different diameters so it could be used for a variety of cables.
Here is an earlier attempt with speaker cable (14ga of that vintage WE cable
). I hadn't thought of the plastic tubing yet and used a piece of brass tube. Another variable is whether or not the heat shrink covers the tubing or not. Left it partially exposed here.