Dan, I think you're pretty close to the mark. After 25 years with Centaurs, the following represents my personal subjective opinion only:
The Funny Pages 39-42 are all rare. If I had to separate the group, I'd say the 40 is the toughest to find (very rare).
The Funny Pages 36-38 are all scarce. I'd say the 36 is the most difficult to locate in the group.
The Funny Pages 35 is uncommon - I have seen handful of them over time (I don't own one, but would like to).
The Funny Pages 3/10 and 4/1 are both very scarce. It may be surprising that I think the 3/10 is more of a toughie than the 4/1.
The Funny Pages 3/9 (not an Arrow cover) is uncommon - I have seen a handful of these over the years.
The Funny Pages 3/7 is scarce (I don't own a copy, but would like to).
No matter how we slice it, they are great books.
STEVE Got Larson?