[MLeake]

In the past, I have used the high thumb grip, with mixed results. Safety configuration seems to have had some bearing on those results.

With extended safety levers, and my long thumbs, I have encountered the phenomenon of inadvertently safing the gun during recoil. Switching to thumb on top solved that issue, and worked well with the Ed Brown safety on my old DW - but did not work well with my Baer. With the Baer, the lever itself was too level, and my thumb biases against the slide, slowing reciprocation and causing some FTRB issues.

(Edit: That diagnosis resulted in part from the thumb oil smears down the left lower edge of the slide...)

I have been told by a gunsmith friend that he only likes thumb high on Ed Brown safeties, as the Browns slope slightly away from the pistol, preventing the thumb from acting as a brake on the slide.

In the case of my Baer, I just had him mill the safety lever down to Mil-Spec, switched to low thumb, and the gun has run perfectly ever since.

A self-defense instructor I know also advocates for a low thumb to assist with retention, if necessary.

YMMV.