Thanks, I'm a big fan of
Gonti's Machinations, I run them in my mono black aggro deck also. The 6 point life swing really helps against aggro match ups.
Sword-Point Diplomacy really puts the opponent in an awkward spot with either choice being bad for them.
As for
Soul-scar Mage, it was a card I considered but I wanted to avoid creatures in the main (except for
Fanatical Firebrand which is more of a 1 mana burn spell and occasional blocker.) I am trying
Firebrand Archer post board for now as it doesn't have to get past blockers to do damage but
Soul-scar Mage could also work in this slot.