I think I,ve asked this question quite a while ago on a Canon forum, but with my shortening memory can,t remember what the outcome was. When I have problem with dust on my sensor, it appears on my images most of the time in the right hand corner of my image. So if I just want to clean that particular area of my sensor with the mirror up, where is the dust, orientation wise as I look directly onto the camera sensor.
Sorry george I can't help with that one, a blow with a rocket blower with the mirror up has always done the trick for me, if his doesn't work it maybe you need to use the swab method, I've never needed to do this so I can't advise.
George, everything is the same as in the olden days ! image is flipped and reversed as it hits the sensor, so if on the final image it is lower right, looking from the rear of the camera it would be upper left on the sensor, looking into the camera (through the lens mount) top right.
Now that is confusing ! Having said that, if you are cleaning the sensor, the practicality of cleaning just one area is pretty slim, just clean the whole sensor.