Some MNK advice needed

So I'm working to try and increase my MNK dps as I am a ninja main and the jobs are so different. I played MNK a lot in 2.0 before I started learning ways to effectively dps so now I'm returning to the class and want to learn how to optimize. I have a few questions:

Should I wait til I hit GL3 to start using my ogcd skills to get more damage out of them? In a fight with lots of jumps and PB is on CD.
Also when bosses jump or I have to run to dodge an aoe, should I prioritize Meditate or form shifting? I've been form shifting but sometimes I really wanna get those stacks up.
How do you know when to drop tornado kick? A lot of bosses don't have telegraphed jumps, the only ones I know off the top of my head being Kalia, Ravana, Bismarck.

And lastly, is it really that huge of a dps loss when we lose GL3 due to a boss invulnerability? Obviously I'm gonna get back up ASAP but I've seen so many posts saying "It's gg on your dps when you lose GL3"

Thank you for your time

Hello there!

Ideally you want to use your OGCDs as soon as they are available in order to maximize dps, however, you also don't wanna use them without being fully buffed first. In the end it really comes down to the situation that you are in. If it's gonna take too long to get buffed (no GL) and the boss is gonna jump soon, then go ahead and burn those CDs. If you already have GL2, perhaps it's better to use B4B and Internal Release in your GL2 rotation and then burn the other CDs once GL3 is up.

If the boss jumps you should always prioritize Form Shift. The main reason is that you don't wanna lose your GL3, ever, and form shifting helps tremendously with that. If losing GL3 is unavoidable due to mechanics, proceed to use TK and then form shift/meditate, just making sure you'll be on Coeurl form once the boss returns. If it's just a quick AoE dodge and you know the boss will be there for you to safely refresh your GL3, then go ahead and meditate.

Regarding TK, unfortunately that's really hard to tell. The only thing I can say is that if you are uncertain whether you should use it or not, then don't. It's best then using it too soon and losing your GL3.

Lastly, I wouldn't say losing GL3 is absolutely GG if there are no tight DPS checks like in Alexander Savage. But yes, it's a huge DPS loss.

disregard a lot of the things people say about monk. 2.0 monk and 3.0 monk are all about 2 different things.

3.0 monk is about maximizing your downtime - be it chakras or keeping GL stacks. In some cases, you will not be able to keep stacks - in that case, stack up chakras. Any time you need to leave the boss for whatever reason, use chakra if it's possible to keep greased - even if you only get 1 stack of it. More chakra is more damage eventually if you don't drop stacks during short downtimes.

other htan that it's what lilyth said, use oGCD's when the ycome up, use cooldowns as they come up, holy IR/B4B to use together when potion is up (this usualyl is only about 20 seconds maximimum), etc.