Thanks for reading, your comments are appreciated.
In playing position the force axis from the pickup is parallel to the top. Acceleration forces perpendicular to the top, acting through the pickup mass during rough handeling, stroage, transport or misshap, are counteracted by the x-bracing as in the original ES-150. The X-braces could extend to the lower bout to pass through the non-crossing kerfed braces, that would have weakened them. So, rather than removing the non-crossing kerfed braces, and risk damaging the top, they are left in place. Also, for example above the pickup, an ES-150 has the fingerboard glued to the top. In this case I left the brace remnants up there for support.
Interesting that tone-tapping the top reveals a strong bass resonance at the center. I suspect due to the mass of the pickup. This is responsible for the full bass tones in the recorded sample. A real sonic winner in this builder's opinion.
https://youtu.be/f4tcIQXNC2E