I have broken down each back brand by similar groupings cards across the entire set, as well as separate spreadsheets per series. The full set view is quite extensive, making it tricky to find a common denominator/sheet number.
Many possible combinations could be removed if no confirmations for that back are known for an entire group. Total combination based on this is @ 5837.
From this view you can quickly see certain card/front/back combinations stick out from the rest. Groups 11, 29 & 36 make up the Elite P350 groupings.
From the 150 series
