Bumping this again...ten years later. :-)
Based on what's visible on the strips and cards themselves, W515-1/2 and the "Little Wonder Picture Series" represent several (at least three or four) printings under one catalog number, since its 60 baseball players are known on ten-card strips, 16-card (4x4) multi-subject panels, five-card "Little Wonder" strips, one-card inserts, and perhaps other arrangements.
W515-1/2 baseball appears with up to 120 cards across several subjects, so at least one printer produced them all at some point.
* #1-60 W515-1/2 baseball
* #1-10 "W515" boxers (needs another number, IMO)
* #1-10 Hollywood actors
* 20 unnumbered "3 lines text" Hollywood actors
* 10 unnumbered "3 lines text" presidents
* 10 unnumbered "3 lines text" western subjects
Example of baseball players on panel with other subjects, (
first found by Dean's Cards.)
(
See Moviecard's "3 lines text" strip page for more mixed sport/non-sport examples.)
In addition to larger art, W515-2 "corrected" #7 Clarence Walker's cap from striped (Phillies) to plain white (A's). The footer text still got his league wrong (NL), as he'd been in the AL throughout that era.
All "Little Wonder" cards use five-card strips and appear to coincide with W515-2 baseball's last twenty numbers (#41-60). I think "Little Wonder" printing exposes internal confusion over photo licensing, as #1-40 cards show somewhat clumsy overprints to add ©U-U photo credits. Compare the cleaner title for #42 Kamm to #24 Stengel's top edge.
The printer miscalculated card widths for that U-U overprint, with middle cards getting multiple © and end cards uncredited.
While the ACC knows W515-1 and W515-2 for size and cropping differences on an otherwise matching #1-60 checklist,
prewarcards.com shared two examples (Fleer Co. and Jersey Ice Cream) of print runs with advertising backs, similar to M101-4/5 baseball. Fleer refers to single-card inserts and Jersey describes five-card strips. This implies that "Little Wonder" strips coincide with the advertising backs that include Jersey Ice Cream. Fleer's "complete set of 120" reinforces that their print run included all the sport/non-sport subjects, cut into single cards. (Unknown as yet if Jersey Ice Cream told kids how many cards their "set" contained.)
Based on baseball players and teams, W515 first came out in 1923. Since 1920s industry magazines show strip card makers advertised identical products for several years, I suspect whoever made W515 also sold these strips for many years, even after its players started to retire or move on to new teams.
One mystery remains, as several W515-2 cards from the #1-40 run show a "dotted G" photo credit, as highlighted on this Waite Hoyt card. It appears to be printed as an alternative to ©U-U that was later "fixed" during the "Little Wonder" overprint. If anyone knows which company used that dotted G logo, it could reveal who printed this set.