With what you have listed I wouldn't be inclined to use the Rares on any of of them. You have a dilemma with Rares as how many do you accumulate before they start taking valuable bag space and you need to use them. I throw all my Rares at Ledgendary's as soon as I get them. My 96% Lugia was Powered to the possible max by Rare Candy. I have over a 100 each on Moltres and Zapdos before now throwing all gained at a Raikou as it will be the best Electric attacker in my collection. No matter what the CP is you need 218 Candy and 205K Dust to Power Up any Ledgenday or Egg Hatch to the game possible maximum.
I wouldn't be using to much of that Dust either.
The reason why is at L34 there is still quite a bit of XP to be collected to get to L38 where your Pokemon can be Powered to the maximum possible for the game. In that time you can catch/hatch better IV% Pokemon.
IMHO the only time you should Power anything up to the possible max is if it's at least 93% IV as the Dust/Candy cost for the increase/gain is huge cost small gain.
Spending some of your favorite attackers to take to Pokemon L30 is not such a bad idea as you can do quite a few without using it all.
If none of the above is a concern use it on what ever makes you feel happy.
All the above is long winded on why you should hold on but if you have to use it best options are:
Tyranitar, the best general destroyer of most things in the game.
Dragonite, good all rounder only 2nd to Tyranitar.
Rhydon, tough as nails and goes well against most things including very well against Tyranitar.
These are all based on attacking as no defender these days can't be beaten with relative ease even by low level players. Monster >3000CP Blissey can be handy for guarding against immediate soloed attacks and can gain you a few extra Gyms hours until they have decayed enough to take down.