With all due caution, the book clipping seems to show just a possible balance.
I had to replace the biplane wings by an equivalent monoplane wing so the stability calculations work. They produce quite similar results.

First picture view of the equivalent monoplane model. Assumed weight is 45 lbs.
Second picture C/G (green, 92% chord) aft of NP (red, 78% chord) like in the book. Stab lifts 6.8 lbs.
Third picture with the C/G ahead of the NP (at 64% chord). Important is that the stab is still lifting (3.1 lbs).
I don't think the undercambered stab airfoil would work with negative AoA.
Question is how to get the C/G that far forward.

Pitch damping is huge, so I still think the model would be manageable even with rearward C/G.