Ben Helium what ...

Nothing to say except that the 50 balloons announcements are indeed a big maximum!
Hint: pre-inflate your balloons to a little less than 50% to the front single air to the Helium: sufficient result to animate the evening and over by balloons filled cylinder.
Also remember to do a test with 1 ball before your evening in order to check that they are well Helium quality and take at least 24 hours otherwise they are likely to be deflated before the evening.