Refer to the post on page 1 with the standardized dimensions for QH compatible implements and go from there. I got my hitch given to me by a family member who had changed tractors and the new one had telescoping links so he didn't want it. My rototiller advertised being QH compatible and already had the 1 1/4" top pin so adjusted the hook to match. eventually i found that tech spec and realized that the pins are supposed to be 15" apart vertically, and i know many will disagree and there are pin kits to adjust the hook height, but in my mind i believe it to be best if you don't have to change the hook height. I still have a bunch to go through, but my plan is to set up or if necessary, modify all of my attachments to suit one hook height. in the case of the tiller, whoever set it up prior to me had the adjustable ears turned upside down so that the pin height was further apart. i suspect that it might have matched the cat 3 vertical standard. my only concern is that many of my attachments were bought and set up for my old tractor, which had shorter 3 point arms than this one, and then you add on more setback for the quick hitch, and I could run into a driveshaft length issue.