So recently I found out about RMS on film and I'd like to know a bit more about it.

I tried doing a bit of research a so far I have that

1. The lower the rating the finer the grain of the film
2. The size of the frame will result in a higher or lower RMS value
3. The RMS number does not represent the sharpness of the film

I've also found a couple of tables for RMS values of different stocks of film but most of them if not all haven't been updated in about 6 years. Anyone know of any updated RMS tables?

I read the technical documentation from Kodak for the Portra 400 film but they only mention the PGI rating.

Any other piece of information that would be useful in learning more about RMS? Or how to test the film stock at home?