Re: Proper Grip
User, supposedly they do not interfere with slide movement. If you look at the first two pics in my last post, you will see fundamentally the equivalent grip. The difference being the thumb(s) straight forward, right one on the safety catch.
I personally would not consider these two different grip positions bar simply an individual variation and a moot point. Observe what works best for you and use that one; I know of one old-timer who shoots pretty darn well with the wrist support method.
One more point, I do approximately eighty percent of my shooting one handed. With the thumb parallel with the slide, I find it to be more accurate of a grip than the high thumb. As well, one has to experiment to realize what is utmost for themselves.