Add an option to PRINT to set the default printer; I suggest /Z:
Since PRINT doesn't wait around for documents to finish printing — or to start printing, for that matter — changing the default printer should probably be handed before printing any documents specified on the command line. Changing the default after printing documents will require another PRINT /Z command, (much) later.
C:\>print /z:*laser* Default printer set to "HP LaserJet 4050 Series PCL 5". C:\>