I guess that is what you call it. The Army and Navy taught that method for the 1911 as I understand it. It's the same grip you use with a revolver, at least when I was trained back in the 60's.
I am 6'4" at 278lbs with XLG hands and very little body fat.
I've shot 41mag,44mag,357mag revolvers. Hot 10mm's, Desert Eagle in 44 mag, 45acp in a 1911, Glock 30/21 etc..
Just a little background (not ment to brag).
At State and fed requals I placed in the top Three of 60 officers (first to fire and finish) and have shot some perfect scores both with Revolvers and 40 cal pistol. Considered an expert in handgun/shotgun/rifle. So if that is what you call it, Yep it works for me!
It was stated that she had short and stubby thumbs. You can shoot with the thumb over or under the shooting hand thumb.
The important thing is that she is comfortable and accurate with the grip she uses regardless of the grip style.
Be SAFE and Shoot often!