Did you have a "barber pole'' on the ASI (Air Speed Indicator) to denote the changing Vne values, (what really was Mmo, I guess) or did you just have a look-up table in the Constellation and the DC-7?
I remember asking someone what value that barber pole was using in a Cheyenne turbo-prop when I got just a shrug. I went home and worked out the different values it gave and found it meant something like Mach 0.33! Coming from the Twin Otter I had never seen anything such as a barber pole before and transonic flow and a Mach limit were just abstract concepts.