I am looking at taking this from Tokyo to Sapporo. I will arrive in Japan 30 May and have my JR passes on order. Does anyone know if the overnighter is still running as I can't find it using Hyperdia. And if it is, if I leave it until my arrival on the 30th or the 31st will I be able to book it for travel 23 May? How quickly does it get booked up? Thank you in advance.