[Espeefan]

It's a very good question, and after thinking about it for a while, what I would do is build the truck with a single steering axle first, take care of the alignment, set the toe in/out, and adjust your servo's arm so that it is parallel with the steering knuckle arm, and then drive it around. See how close you are to achieving a good ackerman set-up. Once you are happy with it as a single steer axle truck, set up your second axle to match the first, and bolt it to the chassis. Reduce the steering throw, little by little, of the second axle, until the truck corners nice, without the second axle fighting the first. When the tires roll without scrubbing or slipping, you've got it!