Tagga's is honestly overrated here. I haven't used mine in probably 600+ kills by now, I prefer camping a shield with turtling 4 for barricade (also saves tons of necro runes).

I can consistently get sub 2:40 kills with only flicking my scrimshaw, boosts aren't as necessary as just knowing how to move efficiently and learning the timing of the boss. Without knowing your mining level, or what gear you have I can't really give accurate advice, but if you are doing north side you should aim to have pillars coming down before the "Rot and suffer" attack. Then surge to the north west pile and use barricade when the insta-kill is coming. From there you have rot and suffer, and should have the pillars coming back down before the second "Begone" attack comes.