Here are some various thoughts on the D303 General Baking and Mother's Bread cards:
As to location of printing of General Baking: I remember reading an older issue of the Standard Catalog which indicated that General Baking was located in Buffalo. However, there was a New Orleans dealer (MARKMAN on EBay) who purchased a single collection of close to 1000 New Orleans cards from the 1910s and sold some of them earlier this year on EBay. There were Kotton, Victory, Coupon, Weil Baking, and a number of other cards specific to New Orleans/Louisiana. Part of this collection included quite a few D303 and D304 General Baking cards, which were clearly collected by the original owner, who lived in New Orleans. I asked this question on the Full Count Board, and no one was certain whether the General Baking cards were printed in Louisiana or printed in New York and distributed in Louisiana. If Mother's Bread was indeed printed in Louisiana later on, I would bet that the General Baking cards were printed there as well. (And if they were printed in both Buffalo and Louisiana, could that account for any of the differences such as the blue vs. green background Bender cards? In fact, do both versions actually exist in the General Baking, or was that just an extrapolation based on known variants in the E106 set?)
As to date of issue of the General Baking: I purchased from the seller mentioned above the Bender and Jacklitsh cards - both of which indicate Baltimore of the Federal League. Bender only played for Baltimore in the 1915 season. He was still on the Philadelphia A's in 1914, and he is represented as a member of the Phillies in 1916 sets such as BF2. That would seem to indicate that General Baking cards were issued (at least in part) in 1915. If the checklist on page 90 of Lew Lipset's Encyclopedia is complete, Bender does not appear on any Philadelphia A's cards in the D303 set, which would seem to exclude a 1914 issue. That would seem to limit the set to 1915. That is, at least in part, the same reasoning that was used to date the E106 and T214 sets to 1915. The Standard Catalog and other guides list the set as a 1914 issue, and should probably be updated.
As for the Mother's Bread cards: Are there any known Federal League players? With what team is Bender listed? (Makes it pretty easy to distinguish between 1914, 15, and 16) It seems likely that the Mother's Bread were issued after 1915, probably 1916. However, the previous assertion by MW that Marquard on Brooklyn means that it would have to be 1916 or later is incorrect, as Marquard played on both New York and Brooklyn in 1915. See the following link: http://www.baseball-reference.com/m/marquru01.shtml
But unless there are Federal League Mother's Bread cards, they would almost have to be issued in 1916 or later.
Also, it doesn't seem that the Mother's Bread cards parallel the Tango Eggs all that well (in fact, the errors in the Tango Eggs set seem unique to it alone, such as the Weaver/Tinker card). Plus the finish and printing of the two sets is much different. In fact, are there any other sets printed with as low a quality as the D303 General Baking? Or does that not really matter? Not sure on that one. Anyway, maybe if the T216 set was correctly broken up into multiple subsets like Lipset's Encyclopedia and the Standard Catalog suggest, then one of those subsets might parallel the 1915 D303 General Baking, and another might parallel the 1916 D303-2 Mother's Bread. Just a thought.
Anyway, it seems apparent that someone should redo the checklists for the Louisiana issues during these years (I include both the General Baking and Mother's Bread in this group). As a start, somebody in New Orleans should stop by MARKMAN's shop and catalog what he has left (several hundred I believe), and get copies of the scans that he used to list the cards that he already sold (if he still has them). [And then buy what he has left and send us all a vintage New Orleans card for Christmas; sorry, I'm digressing.] I really don't know jack about these card sets first-hand, but somebody out there must have a sizable collection that could answer many of these questions.