I do not know how to disassemble that lens, it is back-focusing which means the optics need to be moved out farther from the image place. If it cannot be adjusted with a simple shim, then using the spacer between the lens and adapter will work. Try that first, if the RF and Focus do not agree : then put the same amount of shim material on the RF cam.
A real "hack". Try to find instructions for moving the optics from the focus mount.
There are machine shops that will make shims for you, it is not cheap. A company specializing in repair would have this done, or make the shims themselves. Us DIY'rs- get better at cutting foil, or using braided wire.