it would bee sweet to have a way of obtaining an ideal HI concentration; i.e., no excess, for the type of rxn that wareami describes (boring and safe).
might there bee a chem that could bee added, drop-wise, to an initially flooded rxn, that would lock-up the excess H2O into an inert compound?
if so, it would bee added just to the point of allowing a sign of gaseous HI evolution?
(i can't think of one either)