Thank you! The stones are numbered so that they at least appear to show family groupings. I note that "my" John J. Grant is #167 and his father, James Roy Grant is #166, which means they must be next to each other.
I had been using the CornwallRoots website pictures of the stones, but there's no way to tell from that how they are arranged.
Actually, I'm still not sure about which Grant family I need. Oldest are James Roy Grant and John J. Grant that I'm sure of so far.
I do know now that James R's Lot 15W SSRR 2 was granted originally to Alexander Grant, his father. Awaiting copy of extract, after which we'll try to get the Patent.