30.75" long and 23.5" wide. Each month will be the same because of the blank bits each end.

Make the quilt 4 months wide and 3 months in length

That will make it 94 inches wide and 95.25 inches long.

Add on (at least) 1 inch for each sashing strip and it comes to

97 inches wide x 97.25 inches long

Plus any borders or extra width in the sashing.

Methinks that about right for a kingsize bed.

Another option might be to make the quilt double sided with six months on each side.

3 blocks wide x 2 blocks deep

That would be a total of 73.5 inches x 62 inches (plus any extras)

***** just 1/2" for the SS's Brenda ... (1" cut)**