From my minimal knowledge with Admech, here's my advice.
HQ 85 pts
Magos Dominus - Cyber Familiar, Augery Scanner Decent. Maybe give this guy either a mechinator array or abeyant to boost the survivability a bit, since he's not an IC.
Adsecularis Covenant (10)– Rite of Pure Thought, carapace armour Las-Locks (70pts) good.
Thallax Cohort (3) – lightning guns,1 Multi Melta (150 pts) Again, good.
Castellax Class-Battle Automata Maniple (2) Multi –Meltas, (170 pts) I would keep the multi-meltas on faster units such as Thallax, since you're going to be chasing down skimmers and you need to be able to keep up with them. I would just run these guys with their mauler bolt cannons and have them go after cron troops.
Thanatar Class Seige- Battle Automata Maniple Paragon of Metal 275Very, very expensive for this points level. I would honestly drop this guy (as cool as he is), and use the points to buy another squad of thallax for more -2 cover multi-meltas, and then upgrades.
Hope this helps! Essentially for anti-tank you're going to want anti high-AV with some cover negation (so thallax), and his infantry will be super tough now thanks to the new Reanimation Protocols, so you're going to want to try to negate his armour save when possible so he can't roll as many dice. Typically you'd want to stay out of 24in range to avoid the worst of his shooting, but you have to get in nice and close with meltas, so I guess just hope you can survive his shooting.