2002 Givi 166FZ/PLX166 Interference

I recently purchased the 166FZ rear rack arms and already had the PLX166 side mount arms installed. No matter what I did I could not make the two fit together. I currently just have the rear rack installed so I can use the top box, but would really like to have both options obviously.
Anyone else have this issue, am I just an idiot, or is there some trick to making both fit at the same time?