Cap'n - next time you come over here give me a call and let's ride over to a friends house that has his shop approximately 75% complete and you can get an idea on the "size". His has one double car size garage door and then a single size garage door with a good bit of space on either side. Right now he is building a '69 Chevelle dragster and restoring a '69 Camaro RS. He also uses his shop for painting cars.
I mentioned to my wife about building one behind the house and she said I ain't going to be there long enough LOL so keep me some floor space open