90 Tank returning, looking for a what to do guide

[Rongway]

Outside of completing the main story, if I wanted to get into raiding, what is the best/fastest gearing path to make that happen?

The Savage raids drop a week after the normal raids, so you have a week of normal raiding to get the normal raid pieces that you want and fill in the rest with the new crafted gear that comes out at the same time as the normal raid tier. It's possible to start out in full augmented tomestone/tier2 raid gear from the previous patch but early on in the tier it's especially important to give yourself every edge you can to avoid enrage wipes and deaths that could have been just near-deaths.

What is the best way to find what guilds are recruiting tanks/raid spots?

You might try putting up a /partyfinder listing that says something like "Tank new to XIV raiding lf static for next tier" and see who bites. With the new tier coming out in a few weeks there will probably be lots of groups scouting for new tanks.

Is there a best website reference for "meta" builds/gear for classes?

The Balance folks give gear and rotation recommendations for mathematically optimal play. For some jobs, you'll eventually learn to adjust the suggestions slightly for different speed tiers or specific fight scripts, and they'll even point out some of these situations to you so know what to look for.

[Vicus]

Great, Thanks for the info. I didn't know a new raid tier was coming. Anychance on the date?

[Shurrikhan]

Great, Thanks for the info. I didn't know a new raid tier was coming. Anychance on the date?

I think the most precise date we have for now is simply "late May". 23rd or 30th, most likely.

[Rongway]

Anychance on the date?

There has been no official announcement yet but historically the Mog tome events have gone for four weeks before a patch. The current Mog tome event started on 24 April, so 23 May would be the expected patch date based on that pattern.