Thanks all for the comments!
Yippeee! At last! Both this and your barrel mod will be part of my game from now on.
I have a small request, if I may, as it does tie in with what you're doing at the moment - one mod I requested when Morrowind first came out, and again when Oblivion came out - a requirement for the player to have empty potion bottles in order to make their own potions via alchemy. I always found it silly that a bottle magically appeared whenever I mixed some ingredients. Similarly, consuming the potion leaves the player with an empty potion bottle - which you've done already, so we're halfway there!

I though on that idea long ago, but I didn't know if I could be able to do it. Anyway, you just reminded me about it, so I may think about it and try it, but I don't know if my CK knowledge will allow.
Now that you talk about bottles magically appearing on inventory, let me do a small semi-off-topic here. And I say "semi" because it's about both Refillable Potions and Usabe Barrels. I received a request, or suggestion, for having just one empty bottle type (on Usable Barrels) instead of just a different bottle for each type. So basically, you would have an item called "empty bottle" and when filled it would transform into whatever drink you used (honningbrew, wine, etc.). Personally, as I stated in several posts in different places, I didn't like that idea because of the lack of realism (to have a model that turns into another model).
So I would like to know what you (and other members of course) think about this... It could also apply to this mod, where I use different bottle for each potion type... Would it be better to have just one standard "empty bottle", that would turn into whatever potion barrel player uses?
Right now I like how it is designed, because if I'm carrying "minor healing" it means is a small bottle, and that's what I'm filling, so I get "minor healing" potion back. If I'm carrying two "vigorous" potions (bigger than minor), then I can fill those two. With usable barrels it would be something similar.. but in this case I made it for compatibility with other mods. It would make sense to refill a bottle of honningbrew with black-briar, but it would require a new item type, meaning it wouldn't be compatible with other mod.
Sorry for the long text.. any comments are welcome.