MT4 programmatically resizing and positioning of current chart window

[Christian Anton Schluessel]

Goal: I usually have my charts(over 20) maximized but at certain times, for comparrison, I want to have only two charts filling the whole window: 
one to the left with 100% height and 50% width and another one to the right with the same dimensions. 
I'm aware that I can do this manually but to get it right needs a lot of fuzzing around each time. 
I would prefer to have an indicator with a button in each chart to do this manipulation. 

I added a screen shot for clarification.

I know how to write the indicator, button and events etc. but I'm totally stuck with the resizing and positioning. 
Built-in mql4 functions do not achieve this so I started using user32.dll but I totally suck at c++.

Through hours of google search I got something that at least compiles and runs without error but unfortunately does nothing:

#import "user32.dll"
int GetParent(int hWnd);
int SendMessageA(int hWnd, int Msg, int wParam, int lParam);

bool SetWindowPos(
            int hWnd,
            int hWndInsertAfter,
            int  X,
            int  Y,
            int  cx,
            int  cy,
            int uFlags
);

int      UpdateWindow(int hWnd);
int      MoveWindow(int hWnd,int X,int Y,int nWidth,int nHeight,int bRepaint);
bool     EnableWindow(int hWnd,bool bEnable);

#import

// ... standard indicator code

// my lousy effort

void Update() {
  int wHnd = (int)ChartGetInteger(0, CHART_WINDOW_HANDLE, 0);
  int wHndParent = GetParent(wHnd);
  EnableWindow(wHnd, true);
  bool pos = SetWindowPos(wHnd, 
                          wHnd, // tried wHndParent as well here ... don't know what's expected




    
                          150, 300, 300, 200,

    


    
                          0x0040 // taken from some web example
                          );   
Print("wHnd:  ", wHnd, "   wHndParent:  ", wHndParent, "  pos:  ", pos);

    


    
  // prints: wHnd:  1249230   wHndParent:  49416798  pos:  true
    


    
}
    

// event handler

void OnChartEvent(const int id,
                  const long &lparam,
                  const double &dparam,
                  const string &sparam)
  {
//---
    if (id==CHARTEVENT_CLICK) {
      Update();
    }
   
  }

Maybe there's some c++ guru around here willing to help me out with this.
Thanks in advance