I would use .ini files to control the rotation in mame. That way, you will be sure which way it rotates. I've heard that the autorotate commands (don't know syntax) sometime rotate one way, sometimes another.
make a vertical.ini file in your ctrlr folder and add the rotate right or rotate left command (which ever way goes to your player 1 controls). Then adjust the dip switches for cocktail mode (even though not all support it)
good luck,
Rocky