How to configure font size for Qt4 applications?

[Nikos Chantziaras <realnc@xxxxxxxxx>]

When running Qt4 applications (there's still quite a few of them), they 
use a very tiny font for their UI. When I run the "qtconfig" tool to 
configure the font size, it works initially. However, on the next login, 
KDE overwrites my ~/.config/Trolltech.conf file and puts this in it:

  font="Sans Serif,9,-1,5,50,0,0,0,0,0"

So all Qt4 apps use a 9pt font again, which for me is tiny.

I cannot find a spot in System Settings where that "9" comes from though.