I use the slide stop (lefty, left index finger).

I don't buy the 'loss of motor skills' deal. To get to slide lock I have to have the presence to fire the pistol empty, then drop the empty magazine by pressing the release button, acquire a full magazine, index and insert the magazine to lock, then suddenly lose the ability to press the slide stop.

I don't think so.

Forgive me my nonsense, as I also forgive the nonsense of those that think they talk sense.
Robert Frost