Advice for Purchase

I heat my house with Anthracite (Baker KingStove). Our company is looking at purchasing a new shop. (Metal building about 4000sf) that we use for our mechanic to repair diesel equipment etc... The building we are purchasing does not currently have a heat system and we are seriously considering a coal furnace/boiler.
Any advice/thoughts on what type/size of stove would be good for an open workshop that size? Duct/no duct?
We are in Maryland.
Thanks!

Any idea on the r value in the walls and ceiling? I would start with a btu load calc. a boiler in my opinion will have the highest initial cost, but may work best if you want to break up the area and have a warm office maybe? pros and cons to both. there are many btu load calc programs out there that you can download and use for free and get you closer.