I'd recommend Vanguard or Special weapons.
Both have access to the Crocodile, which is pretty much immune to AT guns and kills every blob of overpowered infantry you can think of.
A well micro'd Firefly behind this beast is very hard to fight off.
If you really like artillery so much, I'd recommend getting used to making forward retreat points to constantly launch arty flare with an infantry section. You need the extra vision for scouting anyways.
And Special weapons is just good to have when your allies are getting wrecked by light vehicles lol
