Mine is 30' wide by 40' deep, x 10'. I have one 16' wide main door on the east 30' side and one 10' wide on the south 40' side (for cross ventilation).
I'm a bit of a hoarder, but I have 2 1950 F-1 pick-ups, 1 59 ford Galaxy, a TR-3 and a 944 in mine. It's not the best but I do get things...