After extensive tests with three different games at three different level ranges I can definitely say that being on a top win streak and playing all three starting boosters is a trigger for lucky boards.
This includes legendary levels, normal levels, nightmarishly hard levels, the lot!
Using this strategy, in about half my levels the two colour bombs start off side by side: Level won. Failing that my first move would be two wrapped candies together or a colour bomb plus wrapped candy together. I got that opportunity on most remaining boards. If that was not available I played whatever first move the game suggested and it almost always miraculously cleared most of the board.
Warning: Occasionally you still need a strategically placed booster near the end or one set of extra moves to keep hold of your win streak, but not often. There may be oops levels where you are playing, but in levels 4000- 5100 and 500-710 I have not encountered any. I can't speak for any other level range. Also I have the top win streak that gives me 2 colour bombs and 2 each wrapped and striped candy. If your win streak is different you may not be so lucky.
Final warning: This will work for one weekend only. So keep crushing while the going is good!