Yes I have both M2/M6/MP with the small dial; and M6TTL with the big dial that turns the wrong way. Here's something I've tried out, with some success.
To increase the exposure with M2, M6classic, or MP, we turn the dial counterclockwise. I try to visualize the rear surface of the dial going to the right: that is, going in the same direction the underexposure LED is pointing in the M6 classic or MP.
Now, with the M6TTL, when I want to increase exposure, I visualize the frontedge of the dial moving to the right. That's easy because the larger dial on these cameras comes much closer to the front of the camera. This automatically turns the dial clockwise.
So: classic cameras, rear edge of dial goes in the direction the arrow is pointing. M6 TTL, front edge goes in the arrow direction.
What do you think?