To catch up here ... Sandy - My testing shows a difference in the shouldering of any panchromatic film developed in PMK - if that differes from your testing - so be it.
Zone 1 is important to me - There are certain things I look for in a negative and without zone 1 it would not be what I am looking for. So - I strive for a printable zone 1 - I also want the thinnest negative I can get and still keep zone 1 - I notice a degradation in sharpness in dense negatives. Zone 1 is like 1db - (if you have good hearing you can just hear 1db) you can just perceive zone 1 - it is near black - it has no other information other that adding one more color to the photo. I want that color - so I care about zone 1. I get zone 1 by knowing my film speed with a particular combination from film to paper including all chemistry and a particular light meter. I meter zone 3 for anything I want to retain texture in the very darkest areas and let everything else fall into place. I take into consideration total range based on high and low spot meter readings and decide if I will need to deveolp at N- or N+ (And I know how that manipulatio will change film speed)
There is definately a difference in the way 35mm an 4x5 catch light and print - My development times are different - the emulsions are different - (eg. TRI X in 35mm has no antihalation layer that I can detect in the prewash - 120 and 4x5 versions have a dense blue antihalation layer) My expectations of each film get adjusted. - I never expect a 35mm to make a great 11x14 print. (Except TechPan) So If the image is going to go big - I use big film. I also think you can get away with a lot more on big film. There is much less enlargement and much more information captured. Kind of a benefit. Tanning developers and LF film give me a "look" that works for the kind of things I like to capture. I was very unhappy with PMK on 35mm and am back to a more common strain of the benzine ring for that.
Truely though, I look at my images and their impact is more from composition and timing than from what chemical I use. The subtle improvements from chemistry just add a different feeling to what is already going on - (Except of course the 50W lit filament in a lightbulb I photographed that was clamped by DiXactol allowing me to read the wattage printed on the glass of the bulb.)