88-note spool end design and dimensions

In MMD 21.03.13, Julian Dwyer makes reference to the free license given
by Aeolian for their tracker bar and spool end designs. I'm curious as
to the specific dimensions and geometry used for the spool ends and
whether a link can be provided for reference to those parameters.

Thanks in advance,
John Grant

 [ At https://www.mmdigest.com/Archives/KWIC/B/buffalo.html is a
 [ reproduction of the article in The Music Trade Review (MTR) that
 [ summarizes the extraordinary meeting of player piano manufacturers
 [ on December 8th, 1908, in Buffalo, New York. The result of this
 [ meeting is now known as the "1908 Buffalo Convention Piano Roll
 [ Specifications." 
 [
 [ The MTR article notes that "Mr. Votey [representing Aeolian],
 [ following the settlement of the perforation standard, offered
 [ a suggestion, which was accepted, to the effect that the
 [ manufacturers adopt for the 88-note music rolls the spool already
 [ being used by the Aeolian Co."
 [
 [ Regarding the adjustable spool end design, Mr. Votey also stated, 
 [ "While this adjustable end is patented, the Aeolian Co. have not, 
 [ nor will not, patent the clutch, offering it for the free use of
 [ other manufacturers."
 [
 [ -- Robbie