I have a couple DoctorSights that I bought after giving up on the Optima.
Dr. is a nice product unless something goes wrong. Then, good luck even getting someone to answer the phone, let alone fix the problem. I'm pretty good with a soldering iron and the dead one is back up and running.
Downside: battery must be magnetic. The positive result of my search for this elusive animal is that I now have a lifetime supply of 3032s for my UltraDot.
Mounts aren't available for the Mk II, but you could modify one of the existing sights to fit (provided you get one with the correct dovetail and know someone with a Bridgeport).
Of the choices, Dr. is the cream of the crop, but I can't recommend it. I much prefer my UltraDot and think that's the best solution for the Mk II.