Advice for leveling my second tank?

I am going to skip over reasons, justifications, or the standard conversation about PLD vs WAR on these boards and just make a note that I have a 50 Warrior. I would like to ALSO have a 50 PLD.

Given that my queues would be instant, and I saved all my leveling gear from MRD, would it be faster to dungeon grind to at least 40 on a PLD?

Fate grinding seemed fine post 40, but I was wondering if it would be faster to get the kill exp from dungeons since I'll be getting the armory exp bonus. I am assuming this bonus does not apply to fate completion EXP, even if it applies to fate kill experience.

Thanks for any advice on the matter.

I believe the +50% exp bonus does apply to FATE completion exp. So as far as I know, you're going to level faster just FATE grinding 1-50 (or maybe CHAIN exp with a group of 8 in select areas/lvl ranges). It's also ridiculously easy to do all this as a PLD (esp. with gear for each level) as:

1) Running in and just spamming Flash on any multiple mob event = Gold medal
2) Once you know where the mobs spawn/timing, see #1 and use Flash to tag the majority of mobs for exp

If you do want to mix it up (I started a brand new character for physical dps because I hated purely FATE grinding so much) and run some dungeons, I recommend queue'ing up for them at the lowest level possible. As far as I know, mobs in each dungeon are the level of the lowest level that you're allowed to enter. This means that you'll be able to get CHAIN exp off them. This is the only time that I ever felt dungeon experience was decent enough to merit doing, even with a static group that could just AE down packs on subsequent dungeon runs.

Addonex

So far on my PGL, I feel like I do get the XP boost for FATEs. I'm not 100% sure on that.

That said, because dungeons depend on others for their efficiency, I would probably stop after Brayflox, and swap to FATEs. The only part people seem to struggle on Brayflox is the Dragon, and that's all dependent on the tank. Since you're in control of that, it seems like a good place to stop. By that point, you can do the Coerthas FATEs, and those are just simply too good.