Do you break many shear pins?
I didn't realise that to get 540/1000 rpm you need to be running to engine nearly flat out. I suppose when working hard you would want it to be throwing all the power it has at the implement, but that's going to cost a fair bit to fuel when running something like a chipper? Unless you get a 540 geared chipper, run the PTO at 1000? That would work for a smaller chipper right?