You wrote: "I also hope to find any other Stradavox owners who are members of the forum." I have 2 Stradavox accordions. One is the quad chamber version (I seem to recall it saying "El Dorado" on it) and the other is a Symphonic Grand model (like yours) that I just acquired.
The quad has beautiful hand made reeds that I was told are "Magnetera". The SG does not have handmade reeds, but it sounds and plays really great anyhow. I mean it has one of the most beautiful tones I've heard in an accordion (and I own ~100 accordions, mostly high-end, for comparison).
For some reason, the white key tops on the SG are badly yellowed, brittle, and cracked. This is particularly surprising since the accordion is in perfect playing shape and in tune. And, the chrome on the grill around the shifts is badly tarnished. I'm wondering if there was a bad batch of key tops produced in Italy at one time, or if this box may have been left in a storeroom window too long ... any thoughts on that, anybody?
It's interesting that the brochure you posted doesn't mention if any of the models shown have or are available with handmade reeds. And it doesn't show the quad chamber model ... perhaps that came later.
