I think you want to stay with both numbers being divisible by 3 as it is a 9P quilt; unless you want to paper piece to yield an 8" 9P.
Use 2 1/2" cuts for the 9P to yield 6" squares and 2" wide pieced sashings. 1 1/2" cuts for the 4P chain block to yield a 6" square. 49 blocks of each yields a 92" square; and you need the pieced sashings and 4P cornerstones.
Use 3 1/2" cuts for the 9" square and 3" wide sashings. 2" cuts for the 4P chain block for a 9" square. 25 9P blocks and 25 chain blocks would yield about an 85" square quilt. Remember you need the pieced sashings and 4P cornerstones as well.
Neither of the above takes into account the pieced setting triangles made up of the chain block.
Hope this is clearer than mud.