I'd like to report that bufo benzoate has poor solubility in water. It took ~ 60 ml of hot water (~80 °C) to dissolve 500 mg of bufo benzoate. This is significant because it shows that the acetone does not have to be so dry upon the addition of benzoic acid, as it will not lead to significant yield loss even if there is some water present. This is another factor to simplify the tek further.

To the solution of bufo benzoate I added a conc. solution of sodium carbonate in water. No precipitate formed but the colour changed from light yellow to dark purple. I evaporated this using a microwave until there was < 10 ml left. A purple precipitate has formed and the solution is currently in the fridge. Will update with pics later.