Fine and Coarse Reeding Varieties of Cuban Coins

Edge of Fine Reeding (FR) and Coarse Reeding (CR) 1915 20 Centavos coins.
Note the difference in spacing between reeds in the two varieties. 
360 view of the edge of Fine Reeding (left) and Coarse Reeding (right) 1915 20 Centavos coins.
Note the difference the star relief as well. 
Edge reeding analysis of the 1915 series. Note the deviation of the FR variety from the trend line for the series. 
Question 1
Edge view of NGC graded fine reeding (left) and coarse reeding (right) varieties. 
Note the difference in the number of reed in between two prongs.
If you still have unanswered questions, please leave your question/comment below and we will add our answer to the list of questions above. 
20 centavos Rays on reverse variety

Cuba 1920 20 Centavos “RAYS ON REVERSE” Variety or Mint Error?

1920 20C RAYS ON REVERSE variety
1920 20C RAYS ON REVERSE variety
Stack’s March 2008 Coin Galleries
LOT 3611 DESCRIPTION
CUBA. Republic. 20 Centavos, 1920. Arms of the Republic. Rv. Star in rays. KM 13.2. Gleaming cartwheel silver displays a wealth of peripheral gold. MS-63 (ANACS).
Update 1
Obverse design features overlayed on both the obverse and the reverse showing perfect overlap of the obverse star and rays and the reverse rays
The overlay shows relative position of dies when the die clash occurred,
courtesy of Ricardo Lopez. 
Update 2
Now for Sale!
Note the very prominent RAYS ON REVERSE!