I like it. It has historical significance and a good ring to it. I could see it working on a little boy without being a GP. That's how I pronounce it, too.
I like
Amadeus Rene! It flows well! Maybe
Amadeus John or
Amadeus Robert or even
Amadeus William . . . as a MN,
Grant Amadeus? Any of those strike your fancy?
On a girl? Absolutely not! No, no, no!