I'm wondering which format to use for stock photography-currently using 6x6 (mamiya c330) and 5x4. Shooting colour trannies on LF costs an arm and a leg, but 6x6 is going to be cropped to fit a rectangular page-so I'm thinking why not use 6x9 ? Either RF back on the 5x4 (convenient but more to carry) or Fuji 690 ? Any thoughts on this appreciated.