I think
Werner and
Gerhard sound okay in
German, but I hate the way they'd be pronounced in English (and I agree with BookEm'Danno:
Gerhard is likely to inspire dirty jokes).
I love
Johannes, but again, I prefer the
German pronunciation, and most English-speakers would probably pronounce it with a J instead of a Y.
Franz is okay...
So, I like
Franz &
Johannes much more as a sibset than
Gerhard &
Werner.