Chlorate Cell Considerations

  Planning to build my first chlorate cell, and there's a few things I want
to consider. First of all, safety. Obviously electric shock is not a
concern, but what about fumes? It would be much more convenient to do this
inside, but I'm told chlorine gas may be produced if the cell is not
"designed properly".
  The cell I plan to use will have a platinized-titanium anode, and a nickel
cathode. I also plan to use NaCl as the starting ingredient, unless I can
obtain some KCl first.
  Then there's the question of what finished product to make. KCl is harder
to find around here, so I only have a few kilos of cheap NaCl that was sold
as water softener salt. Is there any disadvantage to using NaClO3, as
opposed to KClO3?  From what I've read, the only real drawback is its
hygroscopic properties; I assume this could be avoided by sealing the
completed pyrotechnic devices in air/water-tight paper tubing. Or perhaps I
could convert it to NaClO4.....
  Thanks for any advice.