Ok,
  I just tried the smart media card.  I have 12 songs loaded into my QY100.  I formated a card in the QY100 and my choices are to save/load  1 song or all.  I did it both ways.  It takes the same amount of time.  it took about 5 seconds to load all my songs or just 1 song.  As far as the sysex goes, I just don't know the answer.  It says in the manual it will save and load XG exc System messages. I can also bulk dump and load data from and to any sequence program.
George Kaye
Kaye's Music Scene
Reseda, California
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George Kaye
Kaye's Music Scene (Closed after 51 years)
West Hills, California
(Retired 2021)