I think it's flickering because you placed the code that writes the plot labels inside the while loop, so at each iteration you re-write it, just place all that code before the while loop, so that it executes only once before you get into the loop.
And also since you're using waveforms, DAQmx automatically includes metadata with your channels, if you want you have to remove those metadata plot by plot.
You can also optimisze a bit the code to write all the plots' names. See attached VI.
Hope this helps
We have two ears and one mouth so that we can listen twice as much as we speak.
Epictetus
Antoine Chalons