If I understand correctly, John Mor Grant was the first Grant of the Glenmoriston Grants in 1509. He was the younger John and they were all large men evidently. He was the son of Sir John Grant of the Spey. From that time, the Glenmoriston Grants had their own lineage they inter-married with first cousins alot) yet the Chief of Grants was in Strathspey. I'm sure Anne would could give more information.
I sent Jay an email with a lot of my research. I will try to post it here if it will fit in this little box.