Late night brain putty, I now realise! I've re-read the entire thread and on consideration I'd say once more that this technique looks very promising. One should always wear PPE (goggles, gloves, etc.) when using caustic soda, so while we shouldn't downplay the possible 'belching' hazard that sometimes occurs, nor should we overstate it. It appears that with due care this effect can be avoided. That's part of what being careful entails.

In addition, it may be worth mentioning that magnesium hydroxide is still quite alkaline, just not very soluble at all - "one part in 50 000 parts of water" according to my source. It also mentions that "in the presence of ammonium salts it is not precipitated as the sulphide, hydroxide or carbonate" which may be of some relevance. It could well be worth looking for evidence of complex formation between the spice N atom and magnesium ions...