BQ:
Excellent article, thanks.
I would note that (strangely) currently the 1903 S is trending for $100 v the 1901 S's $85 (both in Good-4).
Having collected these pieces for some time, these prices seem illogical to my eye, and I would, therefore consider the 1901 S underpriced, compared to the 1903 S.
Also, currently the 1904 S in G-4 is trended at $50, v the 1913 S at $35.00. Again, this is silly and shows that the 1904 S cain't get no respect.
Good luck with the set, it has been a challenge for me for years.