The simple answer is, "I have no idea". The thought experiment is straightforward though. B&S quote their Potassium Chloroplatinite as being a 20% solution, and this is fully dissolved at room temperature. By mixing Potassium Chloroplatinite powder into very hot water it should be possible to dissolve more than 20% w/v. I don't know how hot "very hot" is nor do I know how much more "more than 20%" is. The same approach should work for the other solutions in the mix.
Originally Posted by eclarke
The challenge I foresee is keeping everything hot enough to avoid crystallisation during coating, exposure and development. And of course the benefits, if any, could be outweighed by the difficulty and cost.