complete waste of time and money to buy nos or other tubes without significant run in time for your new component…. burn in, listen critically, discern where you want to go
I disagree with this. Many manufacturers of tube-based gear ship their products with the best sounding, current production tubes that are readily available and don't increase cost of materials too much. Their expectation is that you will roll tubes - pretty obvious, why else would you buy a tube DAC.
All you need to do is leave your DAC on for a few days, identify what you don't like or want more of (in my case it was a high-frequency harshness/sibilance), and try out some NOS tubes.
+1 @lowrider57 I got my most recent tubes from Brent in less than a week, and that was only because he is really busy.