WDH installation - trailer brackets

After weighing my hitch with my new horse/stock trailer and discovering empty it had 400# hitch weight and if a few sheep moved forward of the axel I had up to 600#, I bought a Curt round bar WDH. The local hitch shop was kind enough to set the height for it, but the seemingly simple task of installing the brackets on the trailer turned out difficult due to a square conduit running inside the trailer frame top outside corner for the wiring, on both sides of the A frame. Photo shows that the bolt will not go in far enough to tighten the brackets. Also a view of the inside of the A frame without the bracket in the way.

I wondered if the simplest thing might be to cut a hole or slot in the conduit and tuck the wires over or under the bolt? Any ideas? I'm just a farmer not a mechanic Thanks