How much LB does a single stun give?

Basically, see title, but here's the story that has me wondering.

I solo tanked Ifrit HM on WAR last night for some FC members who needed their relic. I was also the only one doing any stuns. I wasn't even getting every other Eruption. I tried, but poor timing & animation meant some extras got through. Over four attempts, though, we had enough for LB2 on the nails every time, and enough to push it to LB3 on at least two (maybe three; can't remember).

The rest of the party was 2xSCH, 1xWHM, 2xBLM, DRG, BRD. One of the scholars stayed in Cleric until after nails. Me with Bravura, DRG with DRGThing Zenith, not sure about the rest, but at least four of them needed the fight. DPS didn't seem any worse than your average DF run (though I don't parse, so I'm just estimating based on how long the fight seemed).

So I'm wondering why we had such an easy time building LB. Extra healing? Low DPS? I can't imagine it was just the stuns, because every DF group I've seen, it's cutting close even getting LB2 for nails, even with a PLD that knows how to stunbot. Even with some class stacking, it seemed like we were just swimming in LB.

Limit seems to build up gradually over time while in combat as well as through healing/dps/stunning/etc. so if getting to the nails takes noticeably longer you will probably have more LB available.

Nah on Ifrit HM stuns boost the LB bar a lot for some reason unless they changed it. If you hit all stuns your almost always at 3 LB by nail phase unless DD are just super over geared

The big reason it's hard to get LB3 on Ifrit HM now is because they changed stun DR. Eruptions are going to happen now.