the BIGGEST # I have been told by people is roughly 1275
Math was based on UD's advertised average of one auto/jersey RC per box across the print run. That is a total of 40,774 cards for 40,774 boxes. (40,774/14 = about 2900 cases of product, which wouldn't be atypical for UD - I'd say 26,000 boxes of SPx would have been low for UD.)
then multiplied that by 18 to get a total number of packs: 733,932
then divided the packs by the stated odds of pulling just a Winning Materials (not including Winning Combos) for 52,423
then divided the 52,423 by the number of cards in the set (41), for a final answer of 1,278.