Why not try a tanning developer instead. Moersh Tanol or Pyrocat-HD and mask the grain while you're at it. Hardening fixers take extra time to wash, which in my opinion, actually can cause scratches due to the extra time in water which softens the emulsion. Use the tanning developer coupled with TF-4 fixer minimizes time in water and chems and allows the emulsion to harden sooner, helps eliminate possibility of scratches. Of course, this does not eliminate mishandling of negatives, so don't squeegee the film or wipe with anything, not even wet fingers. A good wetting agent, mixed properly followed by vigorous shaking of the film in the reel to expell excess water before hanging to dry in a dust free area.