Well, I've never seen one of these before.
![Very Happy :D](https://www.audiocircle.com/Smileys/audiocircle/icon_biggrin.gif)
Perhaps the Lampi crew will chime in.
I can tell you the WE 396A is not a drop in replacement for 6DJ8 though I've heard of people doing that with an adapter, but they still aren't that similar. You might want want to try some standard 6DJ8/6922 to start, maybe Mullard, but anything you have to get going . Assuming the Telefunken are in the 12AU7 slot, those are going to be more clear and open on top compared to say a Mullard or Amperex 12AU7. Can't tell what rectifier is in there (GZ-34?), but there's probably a Mullard for that too!