For L 1200:
4x5 box is 143mm W x 118mm D x 160mm H.
MF box is 89mm W x 77mm D x 132mm H.
35mm box is 51mm W x 39mm D x 126mm H.

On all mixing boxes the little feet that hold the bottom of the mixing box the correct distance from the negative are 24mm from the bottom. The lamp holes in the sides of the box are 24mm W x 32mm H. The holes are 79mm from the bottom vertically and are centred horizontally.