You’re right that they’re off-center from a first “symmetry line” you have to draw.
So: you place them on your cutting board. Trace an imaginary vertical bird’s eye view that passes by the center of both. Now based on that imaginary line, move both apples so they’re offset 2/3-1/3 from that line in each direction.
It would make a great homebrew item with a finite # of casts inside, though, as a key pre-boss prep staging…