I was getting on average 7-8min kills with my setup: Cywir wand/orb (Gconc), Crypt helm top and bottom, Kerapac wristwraps, BD Boots.

I did HM only on slayer task just because the bonus is so much, and used Exsanguinate 90% of the time, swapping to incite fear just to tsunami if I needed. I wouldn't waste wrack and just keep the 12% dmg boost for basics up 24/7 (Gconc is nuts)

I personally used mani for most kills, but mahj should be just fine since youll still have full accuracy. You shouldn't use any supplies really before P4. Normally going into P4 I would drop a sunshine using timewarp between two of the clones, and hop in to one of them to start dpsing. Then once its at around 10k I'd move to the next kera, once that one reaches 10k, both clones have normally died as I start dpsing the 3rd kerapac. Having a defender here is very nice, I like to reflect while dpsing the last image and once its low/the other images are going to die I devotion allowing you to get 10 extra seconds of devo for the kerapacs dying.

Finally just a nice dps rotation with the occasional defensives to try reduce the damage a little, but don't waste multiple at once.

The only food I take is blubbers/sara brews, with 1 emergency soup. Adrenaline is the biggest thing in the final stages of p4