So far, after more considerable study and a lot more helpful advice (thanks), I have come up with some revised dimensions. These estimates are just that (estimates) because it would take someone actually measuring the boxes at the national archives to obtain accurate measurements. So, here are the estimates:
Box “A” - (CE 641 and CE 1306): 13”w x 9”d x 8.5”h (still being studied)
Box “B” - (CE 653 and CE 1308): 13”w x 9”d x 8.5”h (still being studied)
Box “C” - (CE 654 and CE 1309): 18”w x 11.625”d x 13.75”h
Box “D” - (CE 648 and CE 1307): 18”w x 11.75”d x 13”h
I have revised the first post in this thread to reflect the changes…