I see the grip as also being very fluid. Working with Fiore (Getty) one can see a lot of movement of the left hand and it really depends on what movements one is making with the sword itself. There are standard pommel grips, open hand palming of the side of the pommel (letting the pommel rotate through movement), grip just below the right hand or off the handle and pommel altogether (as when the pommel is used as the primary weapon), the palm against the back of the pommel in thrusting, and of course no grip at all as in single sword and half-sword. It can also grip as one would in a relaxed or normal grip, meaning opposite the right hand grip (palms facing/opposing) or on the same side when the left hand twists around the handle (palms facing same direction) though that last one is very rare.
From what I can tell, the left hand position and gripping is flexible and dynamic, while the only thing relatively stable (except occasionally with the thumb or index finger) is the right hand. The right hand doesn't move. It's not a death grip by any means, but it stays pretty much right where one would expect up against the guard. For the left hand, though it's primary position is near and around the pommel, it can move all over the place.
This deals with the longsword though, spear and staff allows (apparently) for some right hand movement too. At least that's my observation.
Of course, that's for a right handed person. Left-handers will find the opposite to be true.
Ken
