Here is information for SBR and EFS you requested.
SBR Development time EFS
10 6 minutes 500
9 8 minutes 600
8 10 minutes 640
7 14 minutes 700
6 20 minutes 800
Remember, these effective film speeds are based on the high density range negative needed for palladium printing and would not serve for silver printing, except with a soft grade of AZO.
I actually did some field tests yesterday with the 12X20 J&C Classic 400. The scene was a mountain stream here in South Carolina, very late afternoon just before a thunderstorm. The lighting was very flat with a SBR of less than 6. I rated the film at EFS of 800 and basesd exposure on an average of two incident meter readings, one in the shadows and another in a fully lighted area of the scene. Exposure was 1/2 second at f/32-45. The negative was developed in Pyrocat_HD, at the 2::100 dilution for 20 minutes at 72F. Exposure was about perfect since I have some detail in the heavy shadows, and the resulting density range is about 1.8.
BTW, I just managed to get the camera and gear back in the carrying case before the rains came, but the half mile trek back to the car left me fully soaked.