Not saying this is the best, just how I rigged mine.
I found a small tube and built it up in two places top and bottom using electrical tape. You build it up a little to hold the guide tube away from the receiver a bit. Just keep wrapping the tape around until you have a little roll built up. Then you tape the tube to the side of the receiver with three or four wraps stretched tight. Then find a very stiff thick gauge wire and bend a loop at the bottom something like what you see in the photo below. You sit or lay on the loop with the straight part pointing up between your legs. Thread the guide tube onto the wire and have at it. The receiver will glide up and down along the wire making for a fairly steady hands free motion. Mine does rock side to side a bit but nothing that causes any control problems. A bigger loop would probably solve that. I also silver soldered the wire joints where they wrap around and join to make sure it would cause no skin pinching. You could probably just as easily ball them up with tape. I used a small piece of very light steel pipe, but I’m sure plastic would be fine, something like the barrel from a cheap ball point pen with the guts pulled out. It seems to add no appreciable noise.
I’ll say this, once you got a hands free solution, whatever it is, you never go back to the old way.