I know this is an old thread but just wanted to list some sizes to help people out:
According to sock an average room is 128 units. If we go on the assumption that an average room is basically 8 feet that makes 16 units = 1 foot. He also said doors are 96 units which would make them 6 feet, not very nice to walk through with 6 foot talk players. Taking a look at the goldrush map most of the doors are 112 units high which is about 7 feet (and I remember someone mentioning they made the doors 112 units high)
Revised based on some more calcualations from others:
1 foot = 12 units
1 person (6’) = 72 units
1 door (7’) = 84 units
1 room (8’) = 96 units
112 units (some doors in goldrush) is a little over 9’
I find this pretty good scale to work with as both the textures and feel to it work. Remember bunkers and some buildings might have 7’ ceilings (or lower) as space was generally cramped in WW2 era buildings.