Never use a solid or hydraulic top link on a machine with a long wheelbase attachment. Supporting the tractor by the tailwheel and the front wheels (as in crossing a gulley) will eventually lead to some serious breakage (like tractor transmission case cracking, toplink mount broken, etc) . You should understand the mechanics of the inability of 3 supports unable to conform to local terrain. Use a chain or a rocker link assembly. This puts some slack in the 3 axle constraint (front wheels, rear wheels, tailwheel). Rear tractor axle weight usually wins. What are you you willing to sacrifice ?