Check out section 8.3.9 at
http://www.usfirst.org/uploadedFiles...Robot_RevE.pdf
Particularly check rule 90. The servo wires are 24 AWG. The exception to these rules in the past has been the "Y-connector" cables that allow you to connect two Victors (or Spikes) to one PWM output on the RC. They were 28 AWG as I recall. I don't know as I've seen that exception written in to this year's rules or Q&A forum, so unless I've missed something, I suspect they are not allowed this year.
24 Gauge, three conductor wire can be a bit of a pain to find. I get ours from
www.greathobbies.com but you may be able to find a dealer closer to home.
Jason