How many cablecards should I order from Verizon for a Tivo Premiere XL4? Guessing 2 M cards? My searching is bringing up a lot of noise - can anyone point me to the best instructions for setting it up including troubleshooting (used to be on DSLReports for some weird reason)? Also any prep advice is appreciated. Amazon has just shipped the Tivo - I can call Verizon Tuesday to get cards. EDIT: Oops - Amazon only acknowledged the order - has not shipped.