I have worked on JD planters a fair bit too. The 94 series are a shoe type planter usually. If you plow everything they will work fairly good. In heavy sod they will drag even then. There is a reason that just about every modern planter is a double disk type. Also the depth control at the press wheel is a poor designed compared to gauging the depth right at the planting unit.
As for Leroy stating he does not like the JD 7000 planter. Well that planter took over 75% of the total planter market before Kinze launched theirs and cut into the total.
Send me some pictures and I will try to help all I can.