I think that you could get better results from something like Ilford Pan-F. Reduce the EI to ISO 25 or 32 and develop in Perceptol or D-23 1+1.
To add to what Michael says about CMS 20; bracket, bractet, BRACKET your exposures. Your exposure must be spot on because of the lack of latitude of this film.
In particular I fully agree with Michael's point #6. Some years ago I pursued the lure of very fine grain prints with 35mm film. I was unable to obtain reasonable results after trying a number of special film/developer combinations. Contrast was always too high and the results unpleasant.