I just watched the You tube video of Kurt running the JD 2100 ripper. We are looking at buying one to run on our bean stubble. Which shanks and points do you run? We were thinking the 3/4" shank with the 10" points. We want to try and leave as much residue as possible and still do a good job of fracturing. How much hp per shank? Will a 9330 pull a 9 shank or is 7 enough?