I'm not familiar with the first series and if originality isn't an issue, they remedied this in the 2nd series by leaving that side kick panel basically open and then fixed that with a tall thin cover plate.
I have mine out and could easily trace a pattern of what the factory evolved to. That might give you an idea for your cuts.
You need room if your replacing cages for the nut.(likely reason it just spins) so think bigger rather than just enough.
