You should be looking thru the upper portion of your bifocals, the long-range lens. Adjust the scope eyepiece to focus the reticle, adjust the AO dial to focus the target and you are done.
I am also a bifocal wearer, but recently bought single-vision (distance) prescription safety glasses for shooting. These work better for me than the bi.
At the distance of the scope and action, I don't need glasses at all, only for arms reach and beyond.