I didn't reply earlier since it seemed unlikely that anyone who bought an Ebony SV Wholeplate would bring wet plates near it. However, since you're almost pleading now ( ), here are the dimensions.
- Rear "box" 10-5/8 x 10-5/8 inches
- Rabbeted area 10 x 10 inches
- Depth of rabbet 1/8 inch
- Size of reversible back section that protrudes inch into box's rabbet 9-31/32 x 9-31/32 inches
- Depth of reversible back section that protrudes into box's rabbet 1/8 inch