In 1k game I would drop Ironclad and take frigate. IC is great but it is half of your army and it’ll bring a lot of attentions. Moreover your board presence is very small.
so, if you take frigate in place of IC you’re left with 300 points, and from this point you are able to take more arkanauts, riggers, or heroes. i would go with navigator (dispel, good abilities and powerful artefacts) or Khemist for some ground support or spell in the bottle. Also, I love thunderers, you should try them.