Layout depending on loaded component

[Asperamanca]

I have a TableView, and use a Button as delegate in one column.
Now the row height of the TableView should be at least the height of the Button (depending on font, etc.)
I need to set a property on the button delegate, and the only way I found how to do this was via Loader.

Code of Delegate in file lpad_buttondelegate.qml (part of resources)

Item
{
    anchors.fill: parent
    property Component thedelegate: actionButton
    Button
    {
        id: actionButton
        anchors.centerIn: parent
        width: parent.width * 0.9
        text: buttonText
    }
}

Use of delegate in TableViewColumn:

        TableViewColumn
        {
            id: startButtonColumn
            title: Cpp.CLpad_Mls.getText("LPAD_COLUMN_START");
            movable: false
            resizable: false
            width: tableView.width * 0.15
            delegate: Loader
            {
                property string buttonText: "Start"
                source: "lpad_buttondelegate.qml"
            }
        }

Now I need to adjust the row height. Seems the rowDelegate is the way to go:

       rowDelegate: Rectangle
       {
          height: 30
          // Question: How to use height of button delegate?
          SystemPalette
          {
             id: myPalette;
             colorGroup: SystemPalette.Active
          }
          color:
          {
             var baseColor = styleData.alternate?myPalette.alternateBase:myPalette.base
             return styleData.selected?myPalette.highlight:baseColor
          }
       }

At the moment, I have the row delegate a fixed height. But I would like to set a minimumHeight to the height of the button delegate.
But how do I do that? I suppose, if I use Loader, I will have a fat button sitting in my rowDelegate. That's not what I need - I'd just like to 'peek' the height the button delegate has, so I can adjust the row height accordingly.

Any ideas how to do this?