Actually, when I do hold my tablet(s) with one hand, I do so with the kickstand blade open between my fingers and it gives me a little security of not slipping out of my hand - I can't actually turn it over and use it over my head like a flygrip, although even if I could my fingers and arm aren't that strong to hold that way for very long.
I do not own a flygrip, although maybe you can hold the same way with the flygrip by using it in the kickstand mode?
in kickstand mode yeah you can hold it with the blade between my fingers but its easier of course when both my fingers are in the flygrip