Setting fonts on Windows works, but not on Mac

I have an application that will be running on both a Mac and on Windows, and due to font size differences I've added the following code to override the default settings that come from developing on both OSs.

Code:

---

//***************************/
   //*  Windows-only fonts...  */
   //***************************/
#ifdef Q_OS_WIN
     QFont newFont("Lucida Sans", 9, QFont::Normal, false);
     QApplication::setFont(newFont);
 
     QFont newFont2("Lucida Sans", 8, QFont::Normal, false);
     ui->Calc1LB->setFont(newFont2);
     ui->Calc2LB->setFont(newFont2);
#else
   //***********************/
   //*  Mac-only fonts...  */
   //***********************/
     QFont newFont("Lucida Grande", 12, QFont::Normal, false);
     QApplication::setFont(newFont);
 
     QFont newFont2("Lucida Grande", 11, QFont::Normal, false);
     ui->Calc1LB->setFont(newFont2);
     ui->Calc2LB->setFont(newFont2);
#endif

---

For Windows, this resetting works perfectly for *every* widget but for some reason only works for part of the widgets on my Mac, like line edits and tab headers, but not labels or pushbutton text. I have reset the default fonts just to make sure I hadn't missed any but if that was the case then it wouldn't work on Window.

I can resize the widgets if need be so that my text doesn't get truncated but I'd rather not do that.

Any suggestions? thanks!


-- Kodi