You should get a better return at a charity auction if your clients are any good. I have often seen 100.00 bottles going for up to 500.00.
The idea is to get whisky drinkers at tables to purchase it as a group and they can then drink it amonst themselves at the event.
If you are in the UK a measure is 25mls so that equates to 28 measures but you can round it down to 25 measures if you like for spillage
How you whipp up the crowd is by saying stuff like 'who would can't pay £5 a shot for a 36yo whiskey(which by the way is very resaonable) come on now start me off at 140.00 okay lets say 100 that's only 3.50 a shot' .... and you can pre work out the price per shot up and up and groups may be happy to pay £10 a shot which equates to 250-280.
Or simply sell of the bottle in measures for a tenner each and saves milking the crowd. I can't see why you would not sell 25-28 measures at a charity ball.