I'm using the lower of the two mounting bolts on the seatback, since my toolbox is on the top. There's enough room to get a slim bracket on there, and I hope I can snug it enough to keep from turning. The box will actually help hold it in place...we'll see. If I had some slimmer steel, I mighte be able to mount it behind the toolbox without pushing it cockeyed too much. It will take some test and trial.