What do I need to make this work

So when I first made my board I didn’t put much thought into the wiring so it ended up pretty messy but I want to go back and make this splicing better. What kind of wire do I need to solder to these balancing wires so that i can extend the length?

24 gauge wire.

Just buy extenders. I don’t even bother soldering all those small wires sometimes. Just buy a 6 inch jst balance extender. Amazon or eBay