If she has FCP 5, then she doesn’t have Apple Color.
I would first decide what I want my color to look like, and edit clips accordingly. If you have several to edit, I would create a preset (ex. Preset 01) that gets my color where it needs to be so I can then apply that “Preset 01” to several clips for consistency. If you apply the preset, and it creates a look that’s slightly off your baseline, make adjustments and save that as a new preset (ex. Preset 02). Makes sense?
https://www.youtube.com/graphicsdump
https://www.myr3d.com