Dawn,
I'm using sticky stabilizer on the bottom of the bottom hoop. I'm not using a top hoop because my quilt sandwich is too thick. I tried marking the back of a 4" block, but that is hidden when I try to put the hoop on. I have to line up the center and the top, bottom, and sides. So far, the best I can do is put the sticky stabilizer on the bottom hoop, put that in my machine, mark the center of my block, and using the plastic centering template, get the right placement in the hoop. Then I have my sewing machine do a "check" and I adjust the hoop placement as necessary. It's time consuming and not perfect. Maybe I'm not quite understanding your way.