There is no way, unless you use some other skill ias, like wolf stance oskill or something.
To max hand of god speed with dragon, without rapture (or wolf stance) you need 1680 ias.
I'd use lance or 1h/shield combo, shark rw + shield that adds another 100 damage, that can be competitive to 2h (lower bonus from str but max damage about same).
If you go for shadow tree id look at demiurge skill if anything. Dumping points into euphoria just to get poison pierce I don't think its worth it, too little gain for each hard point.
And plague is too weak to begin with to be a physical immune killer, skill that spreads it is 60%, even with maxed pierce it is too weak vs necrobot imo.