not really addressing the issue at hand, but related, we had to have a 'fountaining' champagne bottle for big, the musical. We found a bottle that a Mento would fit down, filled the bottle with soda, when the actor uncorked the bottle, he dropped in the Mento, and the resulting spray looked great.  The only issue was that broken Mentos don't work well, so we had to find a bottle a whole one would fit into.  Turns out we had an ouzo bottle with the wide neck.  I spray painted the bottle black, taped wine labels on with wide tape sealing the labels down, and the thing was practically bombproof.  All we had to do was mop up the floor and rinse the bottle!  I have a note on that bottle in storage to not throw it away because of this special property! (and to not use it for other shows if possible to keep it in good shape)  (saves the other ouzo bottle we have in stock too)