Thunno, \$ 70 \log_{256}(96) \approx \$ 57.62 bytes

AZ7RAI'#d""TrsZ!.J15343bZZgAJ'1=k.AKDz0sAh212212 221222ZPz1AIdz(0ZN+AI

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A very long port of Kevin Cruijssen's 05AB1E answer.

Explanation

AZ7RAI     # The first 7 letters of the alphabet, A to G
      '#d '# The list ['#']
""T        # With "" appended to it
   r       # Reversed
    sZ!    # Then take the cartesian product of that and A-G
       .J  # Join each inner list
15343bZZ   # Zipped with the binary representation of 15343
        g  # Filtered of where:
AJ         #   the first element
  '1=     '#   is a 1
     k     # (End filter)
      .AK  # Last element of each
         D # Duplicate this
z0sAh      # Get the index of the first input in this list
212212     # The number 212212
221222     # And the number 221222
      ZP   # Paired together
z1AI       # Index the second input into this list
    dz(    # Cumulative sums of this number
       0ZN # With a 0 prepended
+          # Added to the index of the first input in the list
 AI        # Indexed into that list
           # Implicit output