When I set the hinge brackets beside each other, I realized that the pre-drilled holes were offset, which made the brackets not libe up properly. This is a very critical area and location/ size of the holes must be near perfect. I drilled the holes to proper diameter and used a bolt to check their alignment. I then trimmed a little bit off the overhanging end of each bracket. It only needed about 3mm, and I was still able to maintain the proper edge distance for the rivets. I remembered my mistakes from the rudder, and drilled the rivet holes in the bracket BEFORE placing and drilling them on the spar. I didn't need to measue where to place the rivets in the brackets, since these holes were pre-drilled as well. The pre-drilling is nice for Zenair to do, but since each kit goes together slightly differently, a lot of times the holes aren't in the proper place. It'd just be easier and more accurate if the builder drilled the holes. The plans called for 4 AD-5 solid rivets, or two AN3 bolts and two A5 pulled rivets. I didn't want to buy a rivet gun just for a few solid rivets, and the suppplied parts didn't include the necessary bolts. I checked with Tim at Zenair and he said 4 AVEX1601-0512 stainless 5/32" pulled rivets would work as well. I ordered these from Wicks and was then able to finish the brackets using my existing rivet gun. He did say that it was VERY important that the rivet head go on the thinner material side.