Tonight I finished up the fab work for the tiedown bars and spacers. The other night I had drilled the bolt holes for the bar and spacers on the left wing. Tonight I drilled and countersunk the platenut rivet holes in that set, and drilled all bolt and rivet holes in the set for the right wing. I also tapped the bottom of both tiedown bars to 3/8-16, one inch deep, then gave all parts a good scuffing with maroon scotchbrite. I still need to solvent clean and prime before installation.
You may note that the top rivet holes in the top spacers lack the normally accepted 2x edge distance. I'm not overly concerned, as the part is 3/16 thick and should have adequate strength, even with 1 to 1.5x edged distance on one rivet each. The spacer itself is only loaded in compression, and the largest load on the rivet is to resist rotation of the platenuts. At any rate, there's not much I could do about it, as the bolt hole distance to the top edges of the spacers is fixed by the locations pre-drilled holes in the main spar web and the upper spar reinforcement bar.