Hello Darwin, not sure about the harness sizes, but you can reuse the harnesses by cutting off the bad wire leaving 1/2 inch or so soldering new wire to it and heatshrink that. Or just buying the crimp end and slipping that in. the original guage of wire is fine, heavier guage could impact leg movement.
it may be time to heat up the soldering iron then
what size heatshrink would work best in this???