I made my own GHR ‘machine’, which is ridiculously simple and is a take on the Nordic leg curl. I will try and post a pic later.
I put up an old shelf, about 12 inches from the ground, and inverted the mounting brackets, i.e. they are on top of the shelf to take pressure from underneath the shelf rather than on top of it. Using a pad for your knees, you then secure your heels under the shelf and crank out the reps. I also have an anchor point on the wall behind me for band-assisted work, which I need for this exercise. You can fanny around with a loaded BB and other stuff to secure your feet but this is simple and effective. It is also huge personal benefit because my lower back precludes me from doing all forms of deadlifting, and I believe this exercise can be classed as a posterior compound move.