Thanks for this post, I was looking for something that might help out with setting a bunch of queues to Tray1 and Labels for the media type. This is what I ended up with for the Lexmark Universal (the 8 sets the Global or Printing defaults)

"C:\Program Files\Windows Resource Kits\Tools\SetPrinter.exe" QueueName_L1 8 "pdevmode=dmDefaultSource=1,dmMediaType=266"

Thanks again