I guess I dont really see what the worry of the acender above the hitch is. when you are using an acender you are holding it in your hand right? I dont see the scenario where it would come sliding down the rope and into your hitch unless your arm and hand was also somehow disabled.
I use the rope walker system with my climbing hitch as chest acender held up with my lanyard slung over my shoulder. I use the acent tree with a long foot loop attached to it. I have a pantin. I normally do not even attach myself to the acender because I find it to be a pain. I do not mind being attached to the climbing line with only my prussic.
I footlocked double rope for years and so I am used to it.
a lot of the time, I ascend the rope footlocking or with just the pantin with my hitch on my saddle in normal position.
For longer runs I will extend my bridge (like in the video). But for shorter runs the hitch kept at my saddle is very efficient. I take a lock, sit back on my hitch, take another lock, sit back on my hitch, I only use my arms to move the hitch up as I go. the pantin is a little more tiring because you are doing it all on one leg, its also another piece of gear you have to haul around.