How to Dragoon per Second: A DPS Paradigm

[Nucl3arSnake]

Hello everyone, my first time posting in DRG thread although I've been lurking with you for more than half a year now.
I finally gathered some courage to jump in with you, as I have some points I'd really appreciate if I could get your opinion on.

First off, my group is currently at A4S (we're on 3d leg, so you could say we're pretty much new to the last floor), and here's what my gear looks like: http://ffxiv.ariyala.com/RT7Q. Next week I'll probably have 2 twines to upgrade the eso chest and eso pants. Here are my logs: http://www.fflogs.com/ru/rankings/ch.../23108/latest/

I have a few of general DRG questions and two related to A3S specifically (even though it's a farm content for my group now, I want to improve my performance there).
So, for general questions:
1) Despite the dropped head and bracers I'm still aiming for Dervy's balanced set, and the reason why is because my team mates told me that Dervy calculated that starting from 780 crit deminishing returns start to kick in for this stat. Is this indeed true and if yes, is it so for every job?
2) What should I do with cds outside of opener? I noticed I tend to delay cds if I see that my B4B will be up in 20-30 seconds so that I can allight for example B4B+IR+PS. Is it a bad thing to do? Shall I just use everything as it comes off cooldown and don't go for the "stacking with B4B" thing? I understand some mechanics call to the stacking, but I'm mostly asking in general, without regard to any specific encounter.

As for A3S specific questions, there reason why I bring it up is because according to the logs I'm in 26 percentile and I'd really like to go up. My dps is around 1070 atm and I feel like with my gear I could easily go up to 1200. So the questions re A3S are:
1) What do you do with transition to the last phase? The consensus in my team is to use all cds+litany+pots as soon as Pepsiman becomes targetable, but I'm reluctant to do so, because I feel like magnets after the cascade disturb the burst too much. So what I do currently is I still cast litany for my team mates on transition, but delay all of my personal cooldowns until after magnets (so I'm using them during and after protean).
2) I read previous posts and saw that this question was asked a few times already, but I still would like to again confirm this: during add phase the most seem to agree that going with HT+TTT(4?) is the best way? So never Chaos Thrust rotation and never Phleb? And what to do with BoTD? Keep it during the entire phase for buffed Jump and 4th and use Geir only if add is about to get away?

Any other tip you have for me, be it re my gear or useful tricks for either A3S or A4S - I'd much appreciate those.