As I did with the right wing, I attached the thin spacer to the thick spacer with double-sided carpet tape. I drew marker lines on the spar caps, centered on the pilot holes. That let me center the spacers and clamp them in place.
Got them all drilled tonight. Next I'll debur, then I can start laying out the nose ribs.
Thin and thick spacers (stacked) and clamped for drilling.
Opposite face of web. All spacers are drilled and held in place with clecos.