My question is, why not fill only 1 massive golem and then activate Dark Animus? He will get his abilities faster, and you'll have 15 small golems for a bit, but he should still get Full Power at the same time (36 siphon Animas to get all Anima whether you only have 1 or 2 golems, so same enrage.)
To me it just seems much simpler, you'll get out of the dangerous phase quicker to the easy phase. In our 10m kill (which this theoretical method would give Dark Animus his abilities at roughly the same rate as 10m since they use only 1 massive) we didn't have too much trouble handling interrupting jolt and anima font so activating those abilities earlier seems like an ok trade off for ending P1 earlier.
I'm just wondering what I'm missing here, no one does this that I know. Why? Is the few seconds of the 15 active Anima golems that deadly?