MASK Crusaders... working overtime... fighting crime... fighting crime!!! Secret Raiders...
I would start a campaign with yourself and 2 Automa players. If you want more, you can have up to 5. They will unlock a LOT of things very rapidly though, fair warning.
Two is the recommended number for solo plays, per the Automa designers.
Yes, they do unlock rapidly. If I played the game solo, I would probably only play with 2 automa.