James and all:
As no proper biography exists for Spencer that I have seen, I for one would like to see one, and with it, the answer to your query.
He was obviously a capable person and financially astute and after the B&O evicted him from its presidency after one year where he tried to show where B&O's wonder boy John W. Garrett, had been cooking the books for years, those in control of the B&O stock couldn't handle that and he was cast out after just one year and went into the camp of JP Morgan. Morgan placed him as one of the receivers of the Richmond & Danville RR and became SR's first president in 1894 and remained until he was killed in a rear end accident on his own railroad 10 miles south of Lynchburg in late November 1906.
I, too, have often wondered as to his personality and attitudes, especially towards the B&O. Was he above all that or did he have an inward desire to get back at them/it?
I dunno either. would be nice to see somewhere.
I have heard his papers are somewhere in North Carolina, just waiting for someone to do what we ask here.