Shoot a test roll to calibrate the meter to the film and the film to the developer. I guess it's an ASA test.
Choose a developer like T-Max, which I like for medium format since it preduces almost no grain with these T-Grain films and keeps the film speed spot on unlike Microdol-X which will also give no grain but will cut your ASA in half. Both developers have a nice contrast and both have similar times... I use 12minutes 1:1 dilution at 70° or the other I like to use is 8 minutes at full strength @ 70°. Either way do the test rolls so there is no doubt as to what you will get. I get perfect shadow detail and still maintain hightlight details without blocking out. Shott a gray card and include a black and a white towel so you have some texture to look for in the details.
I have to do some experimenting again with my films to see if what I once read in an article that T-Grain films have several sized grains, each size more sensative than the other as well as each reacting to development differently. The article said that if you use longer developing times, all the grain sizes come up making for sharper pictures, higher resolution. I've been very happy with the results I get, in fact I have trouble focusing my negatives, even with a grain scope since the grain is so small and fine, especially with 100 speed film. The 400 speed film has a slightly larger grain but not noticeable untill you start getting into 16x20s. 8x10 grain is not detectable at all.