"My uncle is 80 or so now, and I got the impression that the twins were more or less of his generation."
Almost certainly George Jr. If he were alive today he would be well into his 80's. He lived at Whitney Pier in Sydney and worked at the steel plant. A bit more here:
http://archiver.rootsweb.com/th/read/NS-CAPE-BRETON/2006-10/1161519486