I think you answered some of my questions. I still have some KM left and I agree that it is a great film. When it was available and when it could be processed I also shot 120 Kodachrome. I shot 35mm Ektachrome last week and when it comes back from the lab I would like to have an 8X10 made from one of them and send it to you. I started shooting more slide film at about the time that Type R materials were being phased out. I actually preferred the look of Type R prints to that of scanned and digitally printed slides. Even with contrast masks it was not possible to control contrast as well as you can with scanning and digital printing. The first print order I got from The Slideprinter after they had switched over to scanning and digital printing was a surprise. The slides I has sent were KM. I expected to see the KM grain pattern but instead, when I looked at the 8X10 and 11X14 prints with a magnifier, I saw the pattern of the digital printer. From even a little distance the prints looked very good and I would say that shadow detail was better than what I had seen with Type R prints. The problem with this arrangement for me is that if you look very closely at a print (with a magnifier) and if the print was made digitally the same pattern will appear whether you used 35mm film, 120 film or even 4X5.

Overall quality, from even a small distance, can be better with the larger formats but the resolution of the scan and the dpi output of the printer will make important differences. For making 8X10 prints with minimal cropping on the 8" side there isn't much of an advantage in using 6X9 over 6X7. The more important advantages you would have would be camera back amd lens board movements.

Now I'm curious about how much KM I actually have in the freezer. I have never liked Velvia (50) for people and it will never have the exact same overall look as KM but where sharpness and fine grain are concerned, nice work can be done with that film too.