If the servo is reused Its easy to cut one with a long spliced addition agine at one of the splices and just shorten to the perfect length. Thats three solder joints to be made that can be done in quick time no problem. To splice in a length of wire it is six joints.

I usually get my servo wire from servo city but I think tower has it also.

I keep a full range of soldering irons since it is so handy from time to time in the hobby for example I never use wheel collors and always solder the axles never loosing wheels. I see that one happen every day at the field. But the point is for the simple jobs of splicing wire harness you need only an iron that can be had for ten bucks, just a 25w pencil type and keep on hand some shrink wrap and a little solder. A wire splice is the simplest soldering job of all and an ideal first type of soldering to start with. Exactly like monocoat it soon becomes fun after getting past the fear of just doing it.

John