You should be very happy with Ontrac3 in your combine, and yes you can use the Steer Command ECU to control one. I put one in my 1480 this fall with RTK off a Raven 3000 and was absolutely thrilled. Stayed within 1-2" almost all the time. The auto calibration needed some fine tuning as the combine did seem to weave a bit and would wander severely after crossing rough ditches made with a 3-point rotary ditcher. Backing off the line acquisition values and lowering the steering response number smoothed out the steering and it would pull back on line very well after crossing a ditch.