RE: Return of Lunchbox..
The Lunch Box is different from the other RCs I've built. The steering servo is normally added toward the middle of the build, after the front suspension is assembled, and rx and esc are typically toward the end, just before the body is placed on the chassis. In the case of the LB, however, these steps are done at the very start. Good thing I had a servo handy: A Futaba S3003 standard servo, excellent for steering.
When I built my first RC, I forgot to center the servo before attaching the servo saver. Thankfully it was another vintage RC, the Brat, and so it was trivial to remove and recenter the servo saver. As my batteries were in another room I decided to grab some AAs and use one of the rx battery boxes I had laying around to power and center the servo.
I've only ever used Futaba servos, and I've noticed that dead center will never line up perfectly with the servo saver. It always has to go a little bit one way or the other. I guess that's what trims are for, and fortunately I have a Futaba 2PL so I can set and forget the trims in most cases.