Before you ask, it has been ruled in my local meta that you can in fact take a Soulreaper Cannon in a squad of 5 rubrics so critique with that in mind. The basic idea with this list is that the Rubrics ride up the middle in their rhinos with Ahriman in between, while the Helbrutes form a squad with the daemon prince who provides reroll 1's and protects them against deep strikes and assaults. The
SOT's come in where needed, usually on turn 2 when a hole has opened up in the other player's defenses. The Terminator Sorcerer will usually come in with the Terminators to cast Prescience/Warptime, but the nature of Teleport Strike makes him fairly flexible.
I have 15 points left over that I don't really know what to do with, so suggestions there would be helpful. I'm also not 100% sure on the helbrutes for my dedicated anti-heavy but I don't think there are better options without putting more eggs into fewer baskets.