Has anyone tried planting 15" winter wheat with a JD 1790 planter? What seed disc would you have to use?

 We are thinking about trading in our 12row 30 planter and 30' drill for one 16/32 row 1790CCS to plant corn, beans, milo and wheat.

I would be interested in any experience, good or bad, with any of these crops planted in 15" rows or thoughts on the 1790CCS planter in general.

Thanks, Brian