I couldn't find a single o2 sensor wrench that fit snug when I had to replace my o2 sensor, I think I went with the 22mm socket and cut the wires, leaving a pig tail, incase I had to solder them back together.
Most auto parts stores will rent inpact wrenchs, I own one, and spent alot of time waiting for the compresser to fill up to a high enough presure to run it, but after about half an hour of it impact wrech rattling away, and heating the manifolt with the torch in between, I got it loose.
I recently saw some spray for removing rusted parts that sounded like it freezes the part (shrinking it), you might try something like that, or something that just lubs it, and removes the moisutre from the rust like heat, then you will have a bit of work, but it's well worth it.
Ryland called it. Gave 'er a new oxygen sensor and she runs like new. Well, OK, not quite like new, but pretty darn good for her age.
I grabbed the Sawzall and beheaded the old oxygen sensor (to fit into my not-quite-deep-enough 22mm "deep" socket). It was suffering anyway, so that put it out of my misery. Whacked the breaker bar with the heel of my hand a couple of times, and out it came. Didn't even need to heat up the manifold. Put the new'un in with a shiny new Craftsman 22mm open-end wrench.