Smart way to connect QML GUI objects to C++ audio processing chain?

[Yosemite]

Okay, I am wracked with indecision!

I'm building an audio synthesis application with a minimal "patcher" style interface, in the vein of languages like Max and Pd. A QML scroll area represents the C++ audio processing tree. Drag and drop QML items represent any single C++ audio processing unit in that tree.

Right now, when a QML audio unit is created in the patcher window by the user, the QML item calls a Q_INVOKE method on the C++ audio processing tree. The tree instantiates an equivalent C++ audio class and passes it a pointer to the QML item. The C++ instance is connected to its QML representation via signals and slots. For example:

//QML is created and invokes C++ method to 
//create equivalent audio processor, passes itself
//for signal/slot connection
    function create() {
        created = true
        graph.createItem(this, type)
    }


//C++ synthesis tree creates the proper instance and
//sets the pointer to QML GUI item
void SynthGraph::createItem(QObject* gui, int type)
{
    switch (type){
    case OSCILLATOR: {
        SynthItem* item = new Oscillator();
        item->setMyGui(gui);
        break;
    }
    default:
        break;
    }
}

//C++ class connects signals and slot for communicating
//to its GUI representation
void SynthItem::connectGui()
{
    QObject::connect(myGui, SIGNAL(destroyed(QObject*)),
                     this, SLOT(requestDelete()));

    QObject::connect(myGui, SIGNAL(testSignal(QString)),
                     this, SLOT(testSlot(QString)));
}

But like I said, I'm freaking out! The more documentation I read, the more doubts I have. Is this sensible from a code readability and performance point of view? Should I be making the audio processing classes instantiable from QML instead? Embedding the C++ object into the corresponding QML item? Does it even matter how I do this!? :)