Grenade Arrow question

[Uchuujin]

When using a grenade arrow, do you choose the kind of grenade it emulates when you buy/craft it, or when you fire it?

I could almost see the high cost being worthwhile if you've got one item that can turn into all sort of different blasts for different situations. Need to put it a fire, okay, I have a grenade arrow, so foam grenade. Need to cover your escape, smoke grenade. Need to take something alive, riot grenade. Etc.

[Pantshandshake]

Hey look, it's Space Hawkeye! Hey Space Hawkeye, you got setting on there for a nice brunch?

But in seriousness, I'd think you need to be specific about what grenade goes on the arrow at creation/purchase.

[BigNorseWolf]

When you buy it. Same way as you pick a grenade