I have been curious about this issue since switching to a no-sparge (BrewEasy) system. Adding the same salts as Martin uses in his mash to my system's mash will result in a lower concentration of ions due to the increased quantity of water. But this will result in the same concentration of ions into the fermenter.
If I would increase the salt quantities to compensate for the additional water, my mash water would contain similar concentration of ions, but the wort into the fermenter will contain higher concentrations. This seems necessary (at least to about 40 ppm calcium) due to Martin's statement regarding precipitating oxalates in the mash.
But it seems to me that I am missing something. Any help, as always, is appreciated.