The photo is the customized EMS-L for the binocular use.

Put the EMS on the right-angle gauge. (A desktop and a wall can be a substitute.) You see the eye-side surface doesn't touch the wall closely.(red arrow)

Then,unscrew the three set-screws (blue arrow in the photo) and fix the connecting angle untill the both sides of the EMS will touch the floor and the wall.

This photo is the finished stage of the upper adjustment.

Note the both sides of the EMS closely touch the gauge surfaces. At this stage, the image-inclination adjustment is almost perfect.

Even if some image-inclination should exist at this stage, You can adjust the image angle up to perfect by subtlely adjusting the viewing angle, for example, to shift the right angle toward 89dig. or 91dig.

This is one of the excellent features of the EMS.

Though the above adjusment is done by me, and the users will not have to do that by themselves, I explained that because I would like you to learn one of the remarkable features of the EMS.

This is the diagram drawn to explain how the images rotate in accordance with the change of the viewing angle referred above.
"A" positon is that of the right angled, "C "position of the straight viewing.