now that i have found my way back to september 2013 after taking the giffin grip detour suggested above, i noticed that the photos posted do not show the simple addition of lines drawn with a sharpie to mark the divisions of six that are possible on your grip.
i use my grip to trim and then immediately add slips that i carve through, (see avatar). if you put a straight line from each of the three slider grooves to the opposite side of the grip top you will have marks for a division of three. add ones between those and you have six. they do not have to be engineer like precise, just suitable to help plan a layout. trimming, slipping and carving 20 bowls or plates means the grip is in place for a very long session. wads of clay get in the way but the low, wide sliders are just right.
making concentric rings on the top will help, too. my grip is so helpful all the time but it does have some drawbacks. i cannot use it on the wheel in florida because it is a different brand and i would have to change the settings to make it fit. too hard to see those tiny little grooves. wish jim would move that lizard and mail the unloved grip to me.