Re: Customizig QTableWidget
If you are using QTableWidget and not QTableView, then you retrieve the QTableWidgetItem for your widget's header using QTableWidget::horizontalHeaderItem(). You can customize the item to your heart's content.
QTableWidget is derived from QTableView. In that base class you can find the methods to customize the column width.
If you want the entire table to have the same font, you can set that using QWidget::setFont(). If you want individual cells to have their own font and background colors, then you do that as you add the individual QTableWidgetItem instances to the table.