RV-8 in a 20x20
I'm currently building an 8 in a 20x20. Empenage is strapped to the ceiling using hook-screws and cargo straps and the wings are stored side by side in a wing cradle. I have a 4'x8.5' work table, a 2'x4' roll-around work table, a stationary 2'x5' table holding grinder, drill press, and sander.
Last night I moved the fuselage off the table onto saw horses and still had enough room to walk around the plane. Oh, and I have 18" deep shelves against one wall.
20'x20' is plenty of room.
In fact, there was a car parked on one side of the garage while I worked on the empenage!