Wall mount layout.
I once built a swing down 3 X 8 foot work table in my guarage. The corners had hinges also, as you pulled up the table, the legs swung out for support. Heavy door hinges were used in all cases. 3 on table, 2 on legs.
A wall mounted 4 x 8 would give you no room to work on the back part of the board. Most 4 x 8 are accessable from at least both long sides. As mentioned, rolling stock and other items would hit the floor when swinging down the table.
The fun of modeling would be gone with a swing down table.