I do like the RCA notion. I think you did well in the mini-xlr end cap, rather than trying to build them into the rca connector.
On the wire, I practiced on the cut-off cable, and found that my fingernails did a decent job of stripping. I was able to get the wire exposed. In tinning them, I noticed that the solder just sort of pushed the insulation aside as it wicked into the wire strands.
I also used a razor blade and pushed my finger lightly against it with the wire trapped in between. It took a portion of the insulation off, as it sort of pigtailed; but also appeared to take some wire with it.
Speculation:
Maybe not totally necessary to strip the insulation?
I also found a pair of nail clippers helped in removing the kevlar thread.