Trident or Syn ?

Eithier one should be ok to use for your first one. I’m sure you know the difference so I won’t explain, and if you have any questions please feel free to ask them. Be specific when you ask any questions so that it increases the chances of getting advice from a more experienced member. And also keep in mind, this is your experience, your journey, it will be unique to you.

I'm hesitating between the Helix Trident and the Helix Syn... Which is the most powerful to reach super O?

Which model is the most powerful is totally an individual subjective judgment. In regards to choosing a first Aneros model, I recommend that you first read the following : The Best Aneros model is...
Good Vibes to You !
P.S. I sent you an introductory message with some additional hints and tips to get you started here. Click on your 'Messages' button in the Forums to retrieve it.

They might seem like the same thing, but they are both completely different animals. My first Aneros was the Helix Syn. It is a great toy to start with. But any Trident will get you there. In fact I hope they eventually make Syn versions of the Trident series.

I just ordered a trident.