So far the ink satisfies me very much. It is darker than I expected even when just mixed and it develops into a finer ink with a few days aging. I have shorted it a bit on water. My resultant liquid from ~40grams of galls was 250ml. That is far less than the ~290ml of distilled water called for in the proportions I am using. I've also put in less gum arabic than called for since I have a small bottle of it dissolved in water. I put in 35ml of that assuming that this would leave the ink short of the additional 33ml of water the recipe calls for to dissolve the 15g of gum and 17g of ferrous sulfate. It may not be perfect, but I believe it will serve for purposes of demonstration at the convention's panel on useful crafts after a secular apocalypse. I may also write my yule letters using it.