Camille Build Choices

So I have been trying out Camille for a while but I've run into the trouble of making her build, let me explain.

I've searched and found consistent choice of building her trinity force first and have Ravenous Hydra either second or a component of it until the final build. I tried building tri-force first but it took too long and I didn't feel any powerspike as I was hoping.

So I played with a summoner who said I should build the Hydra first as upon its activation does more damage, so I tried it and I dealt more damage than tri, at least I felt it did more damage, but after a lot of searching I see people saying building tri is better.

So I don't understand, is tri better first or Ravenous Hydra?

Bonus Question: It would be nice to know what masteries people prefer, I currently use Courage of the Colossus.