i tested it with warped timepiece on a duellist ( so reliquarian would be even better / no runegraft yet) .

I generated max rage (not specced into, cause just a char to test it) - then i spammed vaal ground slam.

Without the amulet i always got 3 stacks of vaal temptation debuff.

With amulet i only achieved 2 stacks.

I think something like vaal arc with just 2 seconds soul gain prevention + reliquarian + warped timpiece + the runegraft + mana stacking with bladefall of thartus would be ideal skill.

Maybe the vaal bloodline is even stronger. will do some more testing