Each jack would go on the top of a extended extension ladder. A walk plank could then be set on top of the jacks to span the distance between the ladder. I spent 12 years as a roofer so I've set a few of those (though those are a lot older versions). https://broadwayrental.com/wp-content/uploads/CIMG0061.jpg
Antique stirrups from a gynacoligist? Sorry I probably spelled that wrong since they won't work on me.
This is very encouraging. I will give it a shot. They look expensive online. I am not sure that I need them at least right now. Oh well, I guess I will toss them on the pile of tools.