I just finished building a Midwest Stearman.
The CG is determined but looking down on the top of the assembled plane.
Measure the distance from the leading edge of the top wing to the trailing edge of the bottom wing. Then 25 percent of the total distance from the top leading edge is the CG.
The instructions call for 22 ounces of lead on the fire wall. I moved the weight to the front inside of the cowl. The distance forward, 5 inches,allowed me the cut the total weight in half.

The plane flies like an angel when balanced using a OS 90 FS.

"KLUTZ" the Magnificent