The strut attachment brackets on the trailing edge spars each consist of 2 parts, 19 & 20 for the upper wings, 21 & 22 for the lower. The parts each have a 6mm hole where the rigging pin or bolt goes through, and it's important that the holes in each component in a pair line up with each other. I found if you just fix the parts into place on the spar sometimes they don't line up exactly. I checked with the makers, and the answer is to keep them in line with a 6mm bolt while the parts are assembled.
I found a good quality M6 stainless steel bolt with a smooth shank works very well. I use washers & larger nuts as spacers to position the components on the smooth part of the bolt, and also a miniature G-clamp further along the edge of the components. I clamp the paired parts together into a unit before fixing the first component to the spar, then keep them clamped until I need to separate them to fix the second component, later in the construction of the wing. When fixing the second component I again use the bolt to ensure the holes line up, and leave it in place until the mastic has set
