Quick tip: get a set of Lee ND hard grads instead. That way, you can turn the grad upside-down to use it as a ND filter. However, the hard ND resins only go up to 1.2 (4 stops) max, I believe. Still, you could stack (:o) them.
Then you have a set of hard grads (very useful) and NDs. ;)
P.S. I...