Frame mounted coulters, such as you have shown, are used widely in PA, NY & MD with their older Appalachian type rocks and geology and hardly ever seen anywhere else.

The reason is as you mentioned, if you have a unit mounted coulter that hits a big imbedded rock you have about a 4 ft long skip in the row, with a frame mounted coulter, yes the vee opener still hits the same immoveable rock but there is only a 1 or 2 ft long skip in the row. Frame mounted coulters have the benefit of dramatically increasing vee opener life in these very abrasive soils, even when tilled.

As your dealer mentioned, we at Dawn have a Model 1740 setback kit which is two offset plates that mount at the front on the parallel linkage and move the row unit back only about 3.5 inches - just enough to fit our stem down between the leading edge of the vee opener and the rear edge of the JD frame mounted coulter. Other manufacturers make various length setback kits also.

We then use our standard face plate mounted screw adjust row cleaner on the row unit faceplate with both Trashwheels in the rear mounting holes on our frog so that they straddle the rear edge of the frame mounted coulter, as they do on our Dawn 1572 coulter combo.

The Deere dealers in PA often setup a new planter this way also. JD still sells the frame mounted coulters, primarily for this area.

We do NOT find that the Trashwheels, usually set to run lightly andback very close to the row unit gage wheels, significantly affect the "rock skip" length.

On a 7000 and most planters in the area we do recommend our Dawn 12.75 swept back tooth wheel rather than our standard 14" radial tooth wheel. The 12.75 tends to throw less residue and rocks into the 7000 drive chains. However this is often an issue, no matter whose row cleaners you are using. I would contact a Deere dealer and get the little rock guard fingers that fit near the drive chain sprocket whenever using any row cleaners on a 7000 (pre contact drive) in this eastern area.

Best of luck to you.

Jim at Dawn