So, if I understand correctly, there are a couple of threaded holes on the underside of the shifter adapter that you use to screw the shifter adapter to the Playseat shifter holder?
It still seems like a bit of an awkward set-up, because of the way the Fanatec shifter is cantilevered out from the Playseat shifter holder. It would be better if the shifter sat right on top of the Playeast shifter holder IMO, especially given that the shifter holder isn't that strong to begin with. Can I ask you, is the connection between the shifter & the black rods very firm at least?
I notice that the SRT guys appear to have screwed the Fanatec shifter directly to a plate without using the Fantec shifter adapter. I might try that solution.
All-in-all, the Fanatec wheels/pedals/shifters (especially the CSPs) do not work as seamlessly with the Playseat Evo as the G25.