I use a timer Macro that I hit every time I see the DS cast bar.

/wait 30
/p Death Sentence coming in 5 sec. Stoneskin + Adlo Please! <se.9>

Basically, once I hear the <se.9>, I do one more GCD and wait for DS to pop IB. This also alerts your healers and give them time to top you and cast Stoneskin + Adlo.
Works like a charm.
Now in between, I'd do BB > SP > BB > SP to keep the 10% damage debuff all the time.

As for the divebombs, I use Bloodbath when the Snake spawns as a 30 sec timer.