Call the planter guys at Titan in Graceville MN.  Gary and Carl will make it work.  They have a piston pump they put on the PTO, among lots of other avenues.  I don't waste a lot of breath bragging on service folks, but those guys are playing on a different level from most. 

We just put a 40 gpm PTO gearpump on our 24-30 1200. We're in the process of getting it in the field right now, hope after I finish supper I can tell you "yes, it works.  We're running the vac fans on the PTO pump and the VR drives and raise/lower and markers on the tractor hydraulics.  Early 35 Challenger with 32 gpm.