which happens to be almost identical to the HSS grip (althought the Simple Swing folks call it a "power thumb" grip - and my grip may be a tad weaker than a pure HSS grip....).
I don't always MGS "pre-twist", but I do a small core turn to start my BS in order to get into what feels like the MGS position, and then try to stay as stable as possible on the DS as MGS advocates.
My rhythem (and ball striking) seems to be better this way. I'll practice with the MGS pre-twist when I think I am getting "over active" on either the BS or DS.
So I am kind of a combo of MGS and the Simple Swing (the 1 hr version) but it seems to be working for me at the moment.