The Horn attachment to the root rib and spar is relatively easy. I ended up squeezing all the rivets in this sub assembly. I ended up putting the manufactured head on the Aluminium and the shop head on the steel plate. The huge advantage in taking this approach is that if they ever need to be drilled out, the hole will not expand, the downside is that they are harder to drill out, however, I have a 90 degree drill which should accomplish the task if ever required.
