The customization window closes on day -30. Customization takes place days -29 and -28. Bands are "sent" on day -27 or -26, and you should get an email with a tracking number at that time. Be aware though, that "sent" in this case only means a shipping label has been put on the box and a USPS tracking number has been assigned. It has no bearing on reality whatsoever. It can sit on a shipping dock somewhere for a week or start the journey to your home that day. There's no telling. USPS tracking is a complete waste of time since it is almost never updated until well after delivery.
But in any case, the bands should show up 7-14 days before your check-in date.
Steve