Solid guide, mate
A few notes:
- Kraken, as you said, drops tons of food, so if you're camping Augury bring mostly sanfews (I take only 4 pieces of food)
- Keep Preserve on at all times if using an Imbued heart (and Augury during kills, of course)
- You can't venom Kraken, meaning the Sanguinesti staff > Trident of the swamp (for its passive healing and 1 greater max hit)
- Bring a Hunters' crossbow, MSB, or BP to tag the tentacles
- Spec: Volatile staff spec for DPS > Eldritch staff spec for prayer > BP spec the tentacles for health
- Ring of suffering (i) > Seer's ring (i) for the +20 defence bonuses
- Technically, Ely > Spectral > Dragonfire ward > ... > Arcane (but Kraken drops so much food, I just use Arcane)
Here's my set-up for reference:
EDIT: I'm using BP now since it can tag the tentacles on rapid, whereas the Hunters' crossbow cannot (on Roat) for whatever reason. Also, I double-checked, Preserve does 100% work on Roat.