I have a chance to buy a two wheel dolly or caddy, that pulls behind a truck. It's designed to set the steering axle of a combine or cotton picker in and then tow them in reverse down the highway. My question is: if I used it to tow a tractor (i.e., JD 4020,JD 60, WD45, IH 300, etc.), by placing the front axle or front wheel on the dolly, what is the best speed to drive to avoid damage to the tractor? This is assuming all fluids are in place in the rear end/transmission of the towed tractor. If the rear tires are good and the tractor doesn't "lope", then maybe 20-25 mph? Tell me what y'all think.