I'm also looking into the Dewar family for my mother in law. Norman Dewar was her great grandfather and Roderick was her great great grandfather. If you find any family members before Roderick please share. I'm currently stuck on another family member in her husbands side. I hope to print and give the tree to them for their 50th which is coming up this spring. I have a PDF copy of the Dewars of Glengarry. If you would like a copy please email me firstname.lastname@example.org
and I will forward it to you.