In responce to your question regarding the Leinbach 12" plow, I'm afraid I'm not that familiar with your JD tractor model. I bought the 12" Leinbach plow to break up a section of my hard clay yard for a garden. I was suprised how well the plow worked behind my 21 HP B7500 Kubota which only has R4 industral tires. I think you would be pleased with the Leinbach.
In short, it ain't real pretty, but built solid and works well