Fabricated center section spacers from short PVC pipe unions cut and sanded to ~1.440 which is the measured thickness of my wing spars at the inboard ends. The plans call for 1.385 but I went a little wider to match my spar.
Bolted and clecoed the center section halves together and match drilled the rivet holes. Countersank the nut plate rivet holes. Disassembled and deburred. Reassembled with close tolerance bolts through the PVC spacers in each corner. Riveted the front flange.
Spacers for the center section spar carry throughs
