Just some food for thought but my suggestion would be to look into getting a new(er) unit. That beast may be nice ornamental piece but its probably not very efficient and it's going to be a lot of work keeping a 6000 sq. ft home heated with a hand fired furnace.
When its all said in done you could probably get by on new install around $8k, you'll need about 15 to 20 tons per year to heat a house of that size. If you have good insulation and windows it will lean more towards the 15 ton range. It would not be unreasonable to get it delivered by tri-axle or trailer every year and half....
The benefits of a new furnace is going to include automation, you'll only need to take the ashes out and make sure you have coal available to the unit. Depending on your setup you may only have to mess around with it every 2 or 3 days in the winter. You're going to have better efficiency. There's also the hot water coil for domestic hot water, if setup properly you can have unlimited amount of hot water for practically nothing. A new stoker will probably outlast you if its maintained well.
It's a lot of initial investment but it will pay for itself in a few years, it's all gravy after that.