To make this non-redundant, I propose writing each designation with the lower digit first. So, then we would have, dispensing with the hyphen, 01, 02, 03, 04, 05, and 06 for the inner cube faces, 11, 22, 33, 44, 55, and 66 for the outer cube faces, and 12, 13, 14, 15, 23, 24, 26, 35, 36, 45, 46 and 56 for the other faces.
That might be doable. Let me ponder it for a while, and see what it looks like in implementation.
That might be doable. Let me ponder it for a while, and see what it looks like in implementation.