So I just picked up a few rolls of the new medium format 400TX and plan on developing it in D76 1:1 for 9 3/4 minutes at 68, as per the box and kodak website.
I also plan on shooting it at asa 400.

Why this combination. D-76 is high in sod sulfite and the results won't be as sharp as a higher acutence developer. Try one of the pyro based formulae such as PMK. I woulduse an EI of 200-250.If you are worried about grain try a finer grain film like FP4+

steve simmons