I'm guessing that it should be a near-saturated solution. The concentration could be determined by the MIOX unit by measuring the conductivity of the solution ie by measuring the current flow.

Reaction time could be determined experimentally by using test strips just like you do to verify the MIOX results.

On the other hand, there's no way to determine if you're producing the "mystery ions" as the MIOX people claim that they can't detect them either. I think there's some voodoo going on there. Electrolysis of NaCl should be very well understood by now.