Patrick, nice little set up there. The roof exhaust chimney is in a pretty fixed place. I would add an upside down metal garbage pail to the bottom of it (acting like a hood), then I would add an upside down garbage pail to the bottom of your furnace chimney that your hand bombing, attached to the wall with some swinging hinges. You could probably get away with just using two big stainless steel bowls.
Unless you are gearing up to go in the bell hanger business, make a wire foam cutter for about 20bucks and get some pink foam. It's way faster for patterns like this. Pink foam does better than the white stuff and if you want to step up your surface finish, coat with thinned drywall mud. Look at the stuff kelly makes with foam.
It will be interesting to see how easily the mounting tabs end of the pattern will de-mold with no draft there. It also occurrs to me that some of the sharp corners on the pattern may give you a little trouble, fortunately it should be easy to modify the pattern a little if that does turn out to be the case. Nice design, should be a nice looking casting! Jeff
The lost casting stuff will be a later project, cause I'm kind of busy for it now. The molding was not very difficult, even with the sharp corners. Patrick
