If it's still a dragonair, it might not even evolve to a powerful dragonite. I'm talking about move set.
Charge move dps varies from 31.25 (dragon claw) to 14 (Hyper Beam). Quick move dps one is 15 and the other is 11.28, with a huge difference in attack speed (time to trigger charge move).
In my opinion, moveset is much more relevant than IV. So there is a big risk of waste anyway. I would suggest, if you really want to, evolve it and figure out the moveset. If it's a garbage, curse and wait for the next one. Then you save the candies that you would have used for power up. You really don't care about IV until you have a strong moveset. Or you can wait for a wild dragonite. Good luck!
