Larry,
This is my version of the finishing room. It is 12' X 15', with some kitchen cabinets from a garage sale, some display shelves to store "stuff", two 8-foot T-8 fixtures, a turntable to make it easier to spray projects, a 2,200 CFM tube-axial explosion-proof exhaust fan purchased from Grainger (I spray waterborne finishes only), and a "booth" made of foam insulation. You can view the entire thread here. It is very nice to just walk in and five minutes later be spraying to my heart's content .
Edit to add:
The room is heated by the central A/C and heating systems - both are electrical. I have no windows in the finishing room.
Let us know how your planning is coming along between now and implementation.
Al