You can also check the screen size of the device and then use an 'if' statement to make adjustments as needed.
I used the following code to determine if my app was running on a 3rd edition device and then set the max size of the widgets so they would fit and not break the layout.
I am not sure if thats the proper method as I am just learning but it worked fine for me.
//get screen size
QDesktopWidget* desktopWidget = QApplication::desktop();
//get client rect.
QRect rect = desktopWidget->availableGeometry();
QSize size(rect.width() , rect.height());
if(size.width() <= 250 || size.height() <= 300)