Wing Analysis

Here is the negative 3G case. The struts do not take any load. The required spar cap sections in unidirectional carbon fiber are:
Red - 60 mm2
Orange - 40mm2
Green - 30mm2
Light Blue - 15mm2
Dark Blue - 6mm2

We need to use for each spar cap, the larger of the two sections for the 6G positive or 3G negative case. This means, basically, tapering from 60mm2 at the wing root (required for the 3G neg case), down to about 35 mm2 at the strut attachments (required for the 6G pos case), and then tapering down to zero at the wingtip.

Analysis of the wing in 6G positive loading.
Principal flight loads are handled by unidirectional carbon fiber in the spar caps.
The color corresponds to the mm2 of unidirectional carbon that will be necessary (spar cap section):
Red - 40 mm2
Orange - 30 mm2
Yellow - 25 mm2
Green - 15 mm2
Light Blue - 10 mm2
Dark Blue - less than 5 mm2

The behaviour in negative G will be different because the struts do not have any compression capacity. Negative G is handled by the wing root and it will increase the forces in the center section between the struts.