Thank you. Here is what I tried:
The first solution that came to my mind is what QMcKay suggests in this post: Waiter Screen / Ready Orders
I struggled with passing the command value (order identification) from the rule that is fired once a task is completed to the “Execute Task Print Job” action. Samba does not “know” which order I’m reffering to and prints the template with no content. I asked here in detail: How to create Emre's kitchen display
After that I tried using "Duplicate>[Task Type] " command. This works flawlessly but only when completing one order at a time. I asked here in detail: Duplicate > [Task Type] does not work
Then I tried QMcKay’s setup that uses an addTask() script: Waiter Screen / Ready Orders
It works but since it copies the original task I cannot customize how the tasks looks on the waiter screen. I prepared the data as a custom field in the task printer template like (Waiter={PRODUCT NAME} - {ENTITY NAME:Table}) . Even though it works on the “original” task card on KD, the custom field is lost during copying an cannot be used on the waiter screen.
Finally I gave up and cloned the KD to serve as a waiter screen. I set it to only show completed items and formatted them accordingly. This seemed to work great except I obviously could not mark them as completed (as they would show up on KD again 
).
I installed this “setup” in my restaurant. I found out that the Waiter screen (KD actually) does not refresh. The task that is marked as completed on KD does not show up on the waiter screen unless you click on another entity screen and return back.
Message server is connected, it receives a broadcasted message and plays a notification sound, on the KD screen all tasks appear immediatelly but the waiter screen (which is actually just another KD) does not refresh.
I tried to install every other solution I mentioned in this post and all of them have the same issue.
That is why I asked what waiter screen do you use LIVE - you won’t find this issue when you are testing it on a single PC where you have to open the waiter screen after completing a task.
Thank you very much,
Stroodl