Originally Posted by sakadachi

Right, your horn should be positioned 90 degrees to your servo, radio steering trim centered or use a tad bit of sub-trim to get the horn 90 degrees.

Then place your car on the table so that your steering is straight (front wheels pointing straight).

Now adjust your long steering link rod's length so that your servo can remain in that 90 degree position while your wheels are straight.

(If you have a turnbuckle it makes it easier to setup, but not needed).