I was looking through the codex and it seems like one of our most efficient units might be the Purgation squad with 4 Incinerators. Give them a Razor back to get where they want to go and you are in pretty good shape.

For 155 points you get a mobile anti transport weapon (psybolt heavy bolter), and four guys who can jump out and wreck a squad of almost anything. So starting with this idea and put this list together.

radgrenades, psychotroke grenades.

Vindicare Assassin-145

10 termies, 2 psycannons, 2 daemonhammers, 3 swords, 5 halberds, and psybolt ammo.

5 termies, psycannon, Daemonhammer, 2 halberds, 2 swords.

2X Purgation Squad-160--320
Justicar w/hammer and teleport homer; 4 incinerators. Razorback with heavybolter and Psybolt ammo.

2 TLAC, psybolt ammo.

In most games you deep strike all of your terminators.
Grandmaster will like either make Purgation-scouts, or scoring. Though a scoring assassin might be alright if you have an objective in cover and you think he could just sit on it going to ground if he is in real danger for a 2+ cover save or just popping shots off.
You should be able to open up transports with 6 TL strength 6 shots, 4 TL strength 8 shots, and the Vindicare on the first turn, and an additional 12 strength 7 shots once you Terminators come in. Once the transports are open start flaming.
AP 2 blasts and Meltaguns could be a problem, so those should go before your terminators arrive, or once your terminators get in make sure to protect them with screens and cover.