Thank you for your replies. I am happy to hear from people that have used these lenses on film. So many reviews on Pentax Forums list as a con, "awkward focal length." Perhaps it could be on APS-C, but on 35mm film it's exactly what I'm looking for. I await the UPS truck with bated breath!
The article Pioneer linked to was very good. Thank you! It appears this lens will perfectly mate with my MZ-S. I can't wait to run some Acros or Portra 160 through it with the FA 43mm Limited.