In shadow veil u should spend 4/5 skill points. Leave the one where the bomb explodes when finished.

In shadow pierce, leave the 10% armor reduction one (I have never seen it working, seems buggy or if its working then it doesn't work on bosses) and also leave the one which says that it will do additional small attacks once done with main attack. So 3/5 on this.
Noxious bolt - spend 5/5 skill points. And rest three on health medic, additional 1 medic pack, and the one which increases ur health when charged.