I've not re-rebased my models or played a single game of TOW yet because I'm snowed under with work lazy, but Gyrocopters are a solid bet, not just for the obvious firepower, but also because dwarfs really struggle to pursue and catch things, which is kind of important if the tournament's scoring on victory points.
Units of five Irondrakes with a Trollhammer Torpedo in each also give you way more bang for your buck and durability than warmachines, which makes me sad, because I have a lot of painted warmachines, and can't find any Irondrake models that fit in with my old metal army.