Won't you have to change the channel anyway? WIth DTA you have no idea what channel the Mini will be on when you go to LiveTV.
BOLT(4TB)x2/Roamio Pro (5TB Red)
TiVo Mini x4
Roamio Basic(1TB Red)/Roamio Basic refurb(3TB green)
53TB unRAID2--41TB unRAID3--35TB unRAID1a