code: def _get_mft_zone_size(self, num_clusters, mft_zone_multiplier=1):
          
  
          sizes = {
              4: num_clusters >> 1,           # 50%
              3: (num_clusters * 3) >> 3,     # 37,5%
              2: num_clusters >> 2,           # 25%
          }
  
          return sizes.get(mft_zone_multiplier, num_clusters >> 3)
docs: Returns mft zone size in clusters.
          From ntfs_progs.1.22.