There is no way at current to specify a damage value for that, as the game does not keep track of the damage values of items in it's internal statistics.
You might however be able to (you'll have to increment the score manually) by testing for a projectile via the /effect and /testfor commands.
scoreboard objectives add use_splash stat.useItem.373:16430
I know that isn't the proper way to apply the damage value (if there is a proper way).
Anyone know the correct way to do this, if any?
There is no way at current to specify a damage value for that, as the game does not keep track of the damage values of items in it's internal statistics.
You might however be able to (you'll have to increment the score manually) by testing for a projectile via the /effect and /testfor commands.