Nihil Spellbomb has very little to hit here beyond the occasional Plunder the Trollshaws flashback, and its sacrifice ability does nothing proactive otherwise, so it comes out. Duress is excellent, stripping Counterspell, Snuff Out, or Lorien Revealed before they can protect Thorn of the Black Rose or counter your threats. Go for the Throat adds cheap, instant-speed removal for Spellstutter Sprite or Thorn of the Black Rose to help you win the attrition war for the monarch. It cannot target artifact creatures like Baleful Strix or Mukotai Ambusher, so leave those to Cast Down. Keep Cast Down and the full engine; this is a long grindy matchup where card advantage from Ichor Wellspring/Fanatical Offering wins over time.