Batten stagger, if I have this correctly, is:
  - where the clew of each successive batten, rising up the sail, lies further aft.  The reason for requiring this is to allow a single sheet system to work when reefed. 
  With a double sheet, is this still a necessity?
  Anything I am missing?
  (considering a catamaran, with its wide sheeting base, double sheeting should not be problematic - just a lot of string)