Don't be fooled by youtube vids!
I had recently to deal with some FC mates that wonder why they are not able to pass some encounters, even they had made research about strats and all.
Well, it needs say a couple things about the vids you can see on the interwebb:- People on the vid is NOT geared as you! If you know gears (Glamouring excluded), you can see that people is most of the times in their full High Allagan. When you see a mechanic drops their HP to 50%, most likely if you repeat same mechanic with you and healers in your i80, your encounter stops there. They knows the fight and may happen they just ignored some mechanic because they can. They, not you. So take vids as reference to what happens and when, but with a grain of salt.
- Who is making the vids have a top-class internet. Me too, if stay in AOEs HALF the time the guy stay in, I am hit/slided/wathever. Just be aware that you see other players move later but it is just visual lag, they moved early than you see. This lag does not apply to the guy that is recording the vid, if you see him on the plume 0,5s it is because he really was 0,5s in the plume and not being hit. If you stay on the plume 0,5s and get hit, it just means his internet pwns yours.
Then, watching a vid does not makes you ready. You need do the actual fight to learn how really the fight is. The best experience is do them with your FC, so you will avoid all that rage that comes on pugs with peple expecting all pro there. My 2c.