Possible Clues:

• Seems all very fine to have sat before this
• It's going to be fine for the rest of the week (6)
• Sat before the rest of this
• The Sabbath for most Christians
• Mothering --
• Time for leadership of Saddam Hussein to admit end of reign
• Time off for many
• Time off for good behaviour? (6) (WARNING: Two answers in this special 2500th puzzle require numbers as well as letters. The figure zero must be entered as a capital O.)
• and 6 Down: Returning American wandering legendary path is one of ours
• With 58-Across & 20-Across, U2 song about a disastrous 'Spider-Man' matinee?