What you want to do is add slaves through slaveData.js in the data folder and let the game load.Third, I don't know if its because I have opened up the game so much that tis breaking under its own weight but my Slave pack have been changing to the wrong images, at first I though it was just the old pack I updated breaking but then newer packs I downed where doing it and the further I get in the more unstable it gets. I'm on day 102 and almost every other day it breaks my packs, any existing slaves are fine but any slaves that generate new whether from a raid or the market get busted.
But be warned if you add to many it will load forever or break so keep it reasonable.
You could make multiple version with diffrent slave packs.
The good part about this is it's more reliable as when something goes wrong you can try again.