Harper's father was an accountant.
And I believe the nature of these trusts is they pay whatever in dividends you want them to pay, up to, of course, a certain limit.
Perhaps way back in the 1950's when he worked for George A. Touche & Co. He went to Imperial oil in the late 1950's and worked his way up through the ranks. He was one of the first people involved in computerizing a major corporation. He ended his career directing policy at Imperial Oil, and was able to retire early at age 60 to pursue his passions. He was very much into music, certainly something he passed down to at least one of his children. He also was into history, as was his more famous son, although his focus was more on military history.
You are right that the trust could have been structured to pay a fixed dividend, and channel the rest of the earning back into building capital so I agree my earlier estimate could be very low.