For me the Tri-X was already dead in the water when they discontinued the mighty Tri-X 320 in 120 roll format (was shortly continued only in 4x5" that I even considered converting into this format just because of this film).

I don't know why but the 320 was just like from another planet compared to the 400 although the emulsion supposed to be the same(?) The 400 while good film it just never quite didn't "hit the spot" for me while the 320 did wonders for me and I even shot them in parallel to be sure I don't mess up something between them, the 320 was still the clear winner and the most versatile film I've EVER shot - from portrait, architecture to landscape, it just works everywhere giving images a distinct character while the 400 was just a dull b&w that barely fit doing semi-decent portraits for me, I never understood the fuss around the Tri-X 400 being some worldbeater film while the 320 ran circles around it from my experiences.

Would be interesting to know what was the actual emulsion/backing difference between 400 & 320 versions?

I'd kill for Kodak (erm, or some future aquireing company) to bring back the Tri-X 320 in 220(preferred) or 120 roll format, it was that good that now I'd gladly pay "silly money" ($8+) per roll for it (no joke! ) just to have it back and support it going on.