Sinkhan, your guide, and Pinkbullet3, your comments, were very helpful in clarifying my own thinking, and in freeing ten bank spaces. Thanks very much to both of you. :)
I'd like firemakers to be able to make Charcoal at level 30, and to use that Charcoal instead of Coal to make Steel. That would turn Firemakers into moneymakers (and be a nice alternative to buying or mining coal).