Just my 2 cents.
I have over 25 years of experience with B&W photography, including pure analogue, BW analogue film scanning ->FA printing and pure digital. I worked a lot on Kodak T-MAX P3200, BW400CN and some others, mostly 35 mm, sometimes 6x6 (usually ISO400). Now mostly Canon full frame, a few times Leica Monochrome.
When it came to digital age and BW conversion I was very excited with possibility to mimic analogue look using digital workflow. It turned out not to be so easy, sometimes very difficult to get desired results, not only in grain area but also contrast and tonality.
I play a lot with Silver Effex Pro and I have made <10 (single digit) photographs in the last 2 years that I am really happy with simulation of analogue print look when ink jet printed (I use QTR and Epson K3 Inks). As a rule of thumb, Silver somehow simulates into direction of both Kodak films I have used, but is far from ideal. This is not only about grain, but also other aspects. The final output requires a lot of tweaking, try and error, also number of sample prints.
As for the grain, I always use 2 passes of Silver. First, to make BW conversion from color with NO grain added. Then additional processing in PS or other software, also scaling in correspondence to the final print size. The second pass, just to add grain - with parameters dependent on print size.
Interesting, very often I haven't used the 2nd pass results for the final print - I usually liked "no grain" version on print more, even when my initial target was to simulate grain and although the picture with grain looked good on screen, I didn't like it after print. Maybe it is specificity of ink jet reproduction technique...?
As a summary, simulation of analogue films is not a trivial task, requires a lot of time not to make the picture even more artificial than synthetic digital. Even when you have a lot of good quality tools.
