Thanks ! Found this too -----
How to avoid over-compressing your mix: The TT Dynamic Range Meter - Mastering Media Blog ----- (other link wasn't working). Also, (for anyone) is the dynamic range of a (pre-mastered?/non-mastered?) Brahms 4th symphony much greater (than in rock), and can future forms of very progressive rock possibly try to reach or approach that ? For example, in a long, epic ballad type song with a grand crescendo ending (ff), and with a middle section of just the electric guitar playing light fingerstyle (pp), are these general reasonable dynamic range limits for the final mix at least theoretically flexible, or have they actually been attempted to be pushed beyond suggested limits ?