Wow Khat you are really fast... Anyway if you don't want to see the taskbar HKN has a function for hiding it, I usually put this with my toggle hotkeys hotkey. It helps me see when HKN is disabled vs enabled.

The following code is slightly modified from what Khat already posted.

Code:
//---------------------------------------------------------------- 
// SET PIP CONFIGURATION  
// Usage: <SetPip BigWindowName LittleWindowName>  
// This command is called by <Hotkey F1> which is defined below.   
//----------------------------------------------------------------  
<Command SetPip>     
<TargetWin %2%>
        <SetWinSize 384 216>
        <SetWinPos 1536 864>
     <TargetWin %1%>
        <SetWinPos 0 0>
        <SetWinSize 1920 1080>
     <TargetWin %2%>
        <SetForegroundWin>
        <UpdateWin>
     <TargetWin %1%>
        <SetWinRegion 1536 864 384 216>
        <SetForegroundWin>   
//----------------------------------------------------------------  
// TOGGLE PIP CONFIG WITH HOTKEY 
//----------------------------------------------------------------  
<Hotkey ScrollLockOn F1>
     <Toggle>
        <SetPip WoW1 WoW2>
     <Toggle>
        <SetPip WoW2 WoW1>
//----------------------------------------------------------------  
// TOGGLE HOTKEYS AND TASKBAR Oem3 types the ~ (tilde) or ` (grave) character on most keyboards
//----------------------------------------------------------------  
<Hotkey Oem3>
   <SetTaskbarAutoHide toggle>
   <ToggleHotkeys>
I colored the text that you may need to change. Green is the width and height of the small window, you will have to change the numbers to match in both places colored green. The orange numbers will position the window and cutout in the lower right corner of the screen. This could possibly overlap elements of the game so you may need to adjust it a bit. The reason for the weird (non-100 multiples) numbers is to maintain resolution of the small window and speed up switches, they should be instant if you maintain percentages of the main resolution, in this case I used 20%.

The blue numbers make the main window fullscreen.

NOTE :::: If you want to see the taskbar while playing you will have to shrink the height to about 1060, switch both 216's to 212's, and both 864's to 844's. You will also need to remove the <SetTaskbarAutoHide toggle> command. ::::

If you can't figure out what you need to change post your complete script inside CODE tags, and I'm sure everything can be worked out. Remember to remove login information such as usernames and passwords if you post the full script.