https://www.kickstarter.com/projects/649754189/steampunk-infantry-support-weapons-28mm-miniatures
I'll be eagerly awaiting my initial two batteries (approx arrival Dec) but what weapons to go for?
I'm liking the flak concept as a possible Defence Line stands in/ counts as.

How about a Colt revolver inspired cannon?
The basic Heavy Calibre machine gun.
Plus, future platforms may provide some Ork Mek Gun goodness. I still have the Tesla cannon barrels from the first KS left over and they can be suitably Orkified.