I do own a gallery called 3 Yellow Tulips and we sell both BW and Ilfochrome prints. We have found that for what ever reason nothing smaller than 11X14 seem to sell. The reason seems to always be the same. Our clients need larger prints to fill the space on the wall that they have in mind. People buying art can be on the strange side. We have sold expensive prints and paintings because they match the color of their new furniture. Go figure.
Good luck in all you do.