Really depends on your developer. But the way I do it, Delta 100 has quite a long toe, and I like most
of the exposure on the relatively straight line part of the curve; so I rate it at 50. TMX on the other hand
has quite a bit of contrast not only overall, but way down into the shadows, with relatively little toes;
and it's a film that can block up in the highlights under extreme brightness range, so I expose it at 100,
just as mfg rated. These two films might have similarites in grain, but not in curve shape. They are very
different animals in that respect.