DRK Questions

[Litegrace]

So I used to main PLD pre-3.0 and switched over to DRK when Heavensward released. I'm really enjoying the job, but I just had a few questions (mostly to see how others play the job).

1) When do you pop your defensive cooldowns? I was wondering if you always try to keep one up, or only use it when you are taking big hits. So far I have been popping them when I feel like I'm taking too much damage, or if I know a boss is going to use a tankbuster.

2) DE or SE combo? I know people have said to spam delirium for the added 20 potency, but is that really more useful than the self heal from souleater? Obviously adding dark arts to soul eater whenever possible is good, but for just the basic combo (assuming delirium is still applied to the target).

3) How often/when do you use dark arts on abyssal drain? I have only been using it about once or twice per large pull personally, but I'm just curious here as it uses a LOT of mana.

4) How often (if ever) do you add dark arts to carve and spit?

5) How often (if ever) do you add dark arts to dark passenger?