Old JD offset disc love or hate?

[smb]

I just got an old (probably 50s) JD 6ft series 1200 offset disc for use in the vineyard keeping the weeds down. I pull it with a 62 HP Lamborghini crawler. The hydraulic ram which controls the angle is broken so I am using a chain between the front and rear disks to maintain the proper angle. It seems to work ok, but either pushes too much dirt or does not cut well enough, depending on the angle I use. The vineyard is on 10-15 % grade. Any advice on using this old disc and maintaining it? Anyone have much experience with this model and loves it or hates it? I seems very sturdy.