After being curious for a long time, I finally bought some Diafine recently. I tried TMX 135, and I can't say that I liked it very much. It was *very* grainy and the relatively short toe on TMX was too short with Diafine.(posted 9609 days ago)However, TX at EI 1600 looks really nice, very classic and sharp.
This makes sense when you think about how Diafine works; given the wide developing time latitude, the only contrast control is via exposure to adjust highlight density. If you're not happy with the shadow detail you're getting at the desired contrast, there's nothing you can do.
Dana