Tim,
GREAT SURVEY!!!!

i always wondered this.....Jim R can have some great input here

...this is a rare back i love to collect....most are light blue, i look for this back, only a few are dark blue, i beleive i only have 1 dark blue(manning).....10 total= 9 light 1 dark blue(i might be wrong since i don't have my cards with me please bear with me)
i only have real terrible scans since i don't have my cards with me, but from my list:
LIGHT BLUE:
(2) McQuillen- batting
(1) Jordan- batting
(1) Rucker- throwing
(2) sweeney-batting
(1) Ruelbach-throwing
(1) Griffith- batting (SPLIT BACK)

(1) Ames- hands over head
DARK BLUE:
(1) Manning- hands above head
Always interested in piedy 42s (condition doesn't matter)..email me
GOOD LUCK TIM!! look forward to your results
Peace
Johnny