Oh! Okay, I hope you find a way to do it, I thought that maybe searching for enchantments, but it does't work quite well, because all bows have Unbreaking I, so every single one becomes the same texture, i really don't know how hahaha, I've tried everything.
I've managed to make it work for the Super Speed potion with this:
type=item
items=minecraft:splash_potion
texture=speed
texture.potion_overlay=speed (I'm not sure if this does anything XD)
texture.potion_bottle_splash=speed (I'm not sure if this does anything XD)
nbt.CustomPotionEffects.0.Amplifier=40