100% Dragonite

Looks like you already have invested? I don't understand the question, the Pokémon is level 30 already. Also, as of now the most effective strategy is to bring all your best Pokémon to level 30 because CP gains half after that. I haven't powered up anything above 30 yet.

What comes to your moveset, offensively it's ~6% worse than optimal and defensively ~9% worse than optimal. But even if it had the best moveset I wouldn't recommend powering it up any further unless you have powered up everything else to level 30 that you want to power up.

I would say hell yes. Dragon claw would prolly be better as an attacker but even so, you're gonna be able to get the 3500 Dragonite ppl dream of.
The only downside is that it's not the perfect defender without Steel Wing and a bit off from the perfect attacker. With 3500 CP, who cares! :p

I'd leave it there and work on an over all team ready for battling.