If you don't have a scale G. Hutchins recommends starting with 760ml of water and adding sodium sulfite till the solution level reaches 1 liter. That will make a super saturate of Part B.
I totally misstated this. I should have said sodium metaborate NOT sodium sulfite. G. Hutchins says 850ml of water and pour in the metaborate to reach 1 liter. I just mixed some this afternoon and did it by the book. Will know tomorrow.
sorry for the confusion,