It's easy to do and works like a charm. The "down" and "up" adjustments on the elevation dial, which is now on the left side and adjusting windage, are now respectively "right" and "left". The "right" and "left" adjustments on the windage dial, which is now on top and adjusting elevation, are now respectively "up" and "down". Not the easiest thing to describe in writing, but you will figure it out in about 60 seconds when its on the gun.
At least one manufacturer (Simmons) once marketed a scope designed to mount this way. When you consider that most guns eject to the right, it makes a lot of sense.