What about overall record? I know PS2 did over 500k in 2002 when it got its first price cut and assume Wii or DS had some crazy Mays as well.
Edit: Wii did 675k in May 2008 and I belive thats the overall record.
Edit: After reading this, I'll up my prediction a bit, especially for the Switch
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454
The Steam/GOG key gifting thread: https://gamrconnect.vgchartz.com/thread/242024/the-steamgog-key-gifting-thread/1/