I have 400 Eevee Candies - what shoud I do with them?

"So now I am hoping to use the candy in the hope of getting a Vaporeon with Hydro Pump."

So...

Why the question in the first place?

Go ahead and evolve some then! :D The good thing about Eevee is that they're super common and the evolutions are great for attacking, prestiging and defending as well. Nothing to lose, IV's be damned.

If you aren't set with your team of Vaporeons/Jolteons/Flareons, then you should definitely evolve them now since your chances of getting these 3 are higher currently...

No one knows what the new evolutions will be and how to get them, but if you still need a Vaporeon w/ HP, then having 2 more mons in there would make it harder to get Vaporeon to begin with, let alone, the HP moveset...

If you have tons of them with high IVs and all the right moves, waiting is a good idea...at that point since you already have the perfect Vap/Jolt/Flare...

I had 500+ Candies last weekend. But I was drunk and spend almost 200 candies and 200k dust for powering up my vaporions and I dont really care :) I dont understand people who keep a lot of dust "for future". I get about 20-25k/day. 10gyms+100-250 poks catches everyday after walk with my gf :)