Make the small spruce LWX and LWX pieces for the spar area.
While sizes for the ends are given, they need to be certain angles 35 and 45degrees to fit together. The 2" piece I laminated per plans from 1" sections.
I made the LWY a touch short so added another piece and cut them down. See the first pic. Not a lot of wood in this areoplane.
Following the plans position for LWY and the sheet plan you end up with 0.2" differences. I've defered gluing these in until discussing with other builders. The spar box cutout MUST be big enough so this will drive the measurements.