I have the 10". The problem is that the Koetsu Blue Lace is very long. We can't really get it to sit far enough back to work with any of the protractors. I have the rounded head on my Graham if that matters.
It's no longer than a Coralstone..or any other stone body for that matter (unless I am mistaken) Expect those carts in the Graham headshell to be very near the back of it. I have an older football style Phantom II (elliptical) headshell in addition to the more modern Supreme/Elite head shells. I would recommend you get a Supreme arm rather than the older Phantom II football armwand if in fact that is what you have. If you are using the top line Koetsu, you owe it to your cart to have the top line Grahma arm (Elite) or the second in line...Supreme.