I've used Ez-Steer sytems on several pickups and currently have one on a Stahly truck sprayer.  This truck steers fairly hard and the Ez-Steer struggles to hold the line.  It seem to have gotten worse in the last year and I often just steer it myself.  I do have several Ag leader systems so I'm familiar with them.  Would their steering wheel system have more "power" to turn the wheel?  I'm also using Ez-Boom to run the sprayer and I like the simplicity of that.  Any other options?  I've seen a pickup changed to hydraulic steering but don't know if that would be a good option.  Picture is example of this truck.
for this truck.