Film M frameline question

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For M6 and subsequent Leica rangefinder cameras, the manuals state that the framelines represent the image at closest focus. From this forum and other resources, I understand that to mean a distance of 0.7m for most lenses.

 

The manuals state that as distance to subject increases, the actual image will be larger than what the associated framelines represent, ranging from a 9% increase for a 28 mm lens to a bigger 23% increase for a 135 mm lens.

 

For those of us with older M cameras (e.g. M3, M4, early M4-P) I've read that the framelines assume closest focus distance is 1.0m

 

What is the increase in image size from that represented by the framelines in these cameras? I know many prefer framelines assuming distance of 1.0m, but I've never understood why. I assume the increase will be less than the 9% and 23% that I mention above.

 

What's a good way to use that information, if it's available?

 

I've acquired an M4-P and its framelines definitely encompass more subject area than my M7's framelines. By this, and its serial number (well below 1642551, when the M4-P got the M6 viewfinder version) I'm assuming its framelines are the 1.0m flavor.