Thanks for replies. Like the butcher who backd into the meat slicer, I got a little behind in my work, but onward and upword.
I would like to use the predictor/corrector approach. The instrument would be a refractometer. BTW, an electronic one has a lot of advantages. The light beam is provided by a yellow led, thus the spectrum is consistent rather than whatever the ambient is and it doesn't pass through the sample which is only 2 drops. Shopping at AMAZON I found HANNA Insts HI96811, portable, battery operated, with a LCD 0/50.0Brx, for about $150 about twice a handheld. The steeping and "rinsing" process is slightly different amoung Palmer, Szamatulski(2 books @ MALTOSE EXPRESS) and Russell (Clone Brews). The Idea is check the wort after each step and decide if a calculated corrective addition of ingrediants or water is called for.
For those highly anal retntives, Wikipedia , Brix : Thr Full Wiki , Plato : NBS Circular 440, Table 114 are all Googleable.
A Handbook of Brewing Calculations, Master Brewers Assoc. of the Americas. The center of fermenting being UC, Davis any book by Amerine, Lewis or Bamforth is at a professional textbook level.
Although I hven't checked them out primetab.com/formulas is interesting.