Pic of the inside, this idea should work...
Here is the PCB inside the GC Hori stick... I am thinking of attaching switches to the leads responsible for GC function (leading to the encoder chips etc)... and when switched off, I could use the sticks for a SG/Neo without interference after its controlls are connected to a D-sub 15pin.
Does this sound practical do you guys? I think it should work fine.
PS--> All red lines = Scratch point/ Cut leads... I will add switches for all these points... I could use a 3 4P on-off switchs.