Hi, Bucky sorry I've been silent so long! I didn't know you were asking me for something.

As far as trashing cables, I'd have to take a good look at the cable itself. It's always a risk to start homebrewing on a low-cost cable that has nevertheless been given good engineering tests when the system was designed. For example, if the OEM contacts are held in a rubber or plastic header, soldering will only distort the header and then you'll have nothing useable. I think I'd try to score an alternate set of cables or at least connectors, and build the twisted-pair-with-jacket cable from scratch.

Considering these are low-cost connectors, you need to twist the wires in a stress-free way. The time-honored approach of chucking a hook in a drill, looping the wire over it, and tying the other end to a doorknob will add stress to the wires, and that stress may try to twist or distort the contacts after you build up the cable/interconnect. Partly for this reason, some industries have a standard of not using wire finer than AWG 24 in some cases, AWG 22 or even 20 in other cases. But the wire has to suit the contact.

If I'm not making much sense, sorry! Post some pictures of what you're actually dealing with and I can be more focused. A sketch of your overall planned electrical layout on the bike, or the options for the installation, would also be useful.

I see you're on an island in Washington State. Salty air? Any history of cable or connector corrosion due to that? Gross-looking green or blue crud?