Most of the farmers around here that use a disc use an offset one. From what I have seen the offset does a better job then the tandems, but I have also heard they "pull" a lot harder. I have never seen a small offset disc for our tractors. I was thinking about building one 7' wide or so but was curious if there was a reason we do not see them and also if they really worked better than a tandem or it was just my imagination.