Park yourself around the kobloid mines at outer la noscea.

There are certain FATEs that revolves around the mine itself in a relatively fixed rotation and their cycle rate is pretty fast. And they are all NM type FATEs

The chain usually starts with:
The Miner in the Mirror - right at the entrance into the mines, gold will yields you 18k XP
Stopping the Shakes & Making the Rounds - inside the mines itself, gold yields 19.7k XP
Full Metal Alchemist - inside the mines itself, gold yields 21k XP

Due to the fact that it is a Atma generating area and also the FATEs are part of daily beast tribe quests, you will always see enough people doing the FATEs and each of them usually end under 3-5mins.

I brought my lvl 45 WAR there on last Sunday late noon, grinded there until evening where I went out for quite a while for dinner, and return to grinding until 11pm for raid and I gained 3 levels there (according to xivpads, total of 1,519,160xp gained that day).

The next day, I logged in after work and grinded again and it reached 50 before raid starts.

I say it's a pretty good spot.