TMZ has quite a bit of grain, to state the obvious you are probably going for that "grainy look". If you are happy with the metering in your camera just get a reading at 800 for a given f-stop/shutter speed then add 1,2 or 3 stops for a 1600/3200/6400 rating. If your camera has an apeture priority "A" setting on the shutter speed dial it should also have up to a +/- 2(stop) compensation on either side of the "A" so you may be able to meter at 1600/3200 iso.(posted 9477 days ago)Good luck!!
P.S. use a developer with high sharpness or the grain will look fuzzy.