I used a lot the Karaoke window to sing along with my family. The display of the text is great you can zoom the text as big as you like for easy reading. We can even display the notes so some one can play along too. The only problem is that you can't zoom the notes to have bigger notes. Is it possible to fix that? Also some times the notes scroll freezes while the music keeps playing. Is that a bug too? Any help is appreciated.
I'm not sure about your last problem, but I know that you can customize lots of things from Score>Display setup. It might help you. You can also go to File>Printing options, where you have an option to scale the symbols on the screen.