Mech Tau is definatly a hard nut to crack than regular Tau for Grenadier Lists.
A couple of things to help:
Fire Support Autocannon Squads. Autocannons are great vs Devilfish and good VS Tau in General, and that is what you need to kill them. I would have two squads in a Grenadier Army + 1 Lascannon Squad.
Two Basilisks: Put one on each long table edge (assuming it is not a Cleanse mission), and you can reach the whole board.
Don't take any other Tanks: I find they get popped fast by the Hammerheads. That or hide your tanks until your HWs have neutralized the Hammerheads.
Cameoleline: A very worthwhile Doctrine against Tau.
Three Veteran Squads with Lascannons or Autocannons: Infiltrate them into good lines of fire to pop HHs/DF.
Use your Grenadiers for taking out Stealths, capturing objectives and mopping up transportless Firewarriors.
Hope that helps.
A couple of things to help:
Fire Support Autocannon Squads. Autocannons are great vs Devilfish and good VS Tau in General, and that is what you need to kill them. I would have two squads in a Grenadier Army + 1 Lascannon Squad.
Two Basilisks: Put one on each long table edge (assuming it is not a Cleanse mission), and you can reach the whole board.
Don't take any other Tanks: I find they get popped fast by the Hammerheads. That or hide your tanks until your HWs have neutralized the Hammerheads.
Cameoleline: A very worthwhile Doctrine against Tau.
Three Veteran Squads with Lascannons or Autocannons: Infiltrate them into good lines of fire to pop HHs/DF.
Use your Grenadiers for taking out Stealths, capturing objectives and mopping up transportless Firewarriors.
Hope that helps.