Use a 1 or 1-1/4" holesaw (I recommend the Bosch ones) in a drill press to cut holes out of 1/4" aircraft plywood. The "waste" material (wood donuts!) from making the hole are nicely formed 1" round 1/4" thick discs with a 1/4" pilot hole in the center to clear a 10-32 or 1/4-20 bolt. You can fuel proof them and stack them up as high as you need. In your case you'd need 16 of these little pieces.

Some people buy wood dowel rod, cut it to length, and then center drill them. I like the plywood pieces better, because with the cross-ply, I'd think there would be less chance of it cracking.