The 3 to 1 thing is the closest you can get to doubled rope. Hip thrusting but have even more mechanical advantage and it self tends. On spreading trees it works swimmingly, that's pretty much how i did work positioning with my rope wrench, or when climbing industrial with a petzl rig. An ascender with a revolver CRAB is all you need, and you can still redirect like normal srt. It's just a different way to climb, much more versatile than doubled rope imo because of the self tending, more ma, and ability to redirect.