Better information requiring strategy to make switch? (3-3)
I believe the answer is:
tic-tac
'better information' is the definition.
(system of signs used to communicate betting odds)
I can't explain the remainder of the clue.
(Other definitions for tic-tac that I've seen before include "Racecourse bookmakers' signalling system" , "Bookies'' system of arm signals" , "Bookmaker's arm signals" , "Racecourse bookmakers' telegraphy" .)