Evolve a 100% Dratini or Wait?

Just evolve the Dratini; you're overthinking it. :P

No jst send it to professor for research

Evolve it.

I would transfer to the professor

You should transfer it, your Dratini is only 100%. Over here we don't accept anything that is less than 110%. Wait till you get a 110% Dratini and evolve that one instead.

Transfer forsure

There's no use saving for things that may or may not happen like move set revisions. Just evolve the little snek.

Since you don't really need it you might as well wait; in order to use it maybe make it dragonair and power up for some prestige tasks? And when you decide not to wait anymore just evolve it; you will however max it no matter the movesets.

Question would be do you have enough defenders & attackers? If so I'd wait. There's no need to risk getting SW/HB. You have the best possible movesets already so I'd be patient to see if any new movesets come in a few months. Your candy isn't going anywhere lol.

Power up to the max before you evolve it, then transfer all of your Dragonites.

My friend is facing a similar situation. I recommended to him that he holds onto it FOR TRADING PURPOSES. As you menteioned, you already have some fantastic ones with DB/DC. You could wait, or you could roll AND hope they change movesets in the future, such that yours becomes a legacy one