I have begun researching this family on behalf of my newly-married granddaughter, Mary Anne Guthrie Schensky.
I have information on the 10 children of Charles Edward and Charlotte Singleton, passed on by Ann, dau Charles Eugene Guthrie, including your grandmother, Thelma Guthrie Sinning. The line seems to run Charles Eugene, b. 1935; Clifton w. b. 1908; Charles Edward, b. 1879; William James, b. 1855; to William C. m. 1849 Margaret Crews (I think! but am not all sure).
My information is sketchy at this point. However, if you see a connection and would be willing to share information, please e-mail me. I am particularly interested to know where this family originated in Europe.
Julie Colton <firstname.lastname@example.org