You could just run a figure 8 in a rappel configuration. Then set a friction hitch on the running end below the figure 8. This would allow you to descend one handed and "lock off" without having to have a figure 8 with ears. I did this for 2-3 years before I looked into other means of descending. It definitely works well and I still usually keep a figure 8 and prussik cord in a pouch just in case.
The way to set it up is to just run your figure 8 as normal and tie a prussik (or a better friction hitch) in the system below the 8. I would then clip that to my right side lineman's loop. I'd tie an overhand and clip that back into my bridge carabiner as a safety and then when it's time to descend, simply unclip the overhand, untie is and squeeze the friction hitch.
It doesn't create much heat/wear and tear on your ropes because the bulk of the force is on the figure 8, which is smooth and the friction hitch is easy to break loose but not dangerously so.