Ric, thanks so much for this post and the very helpful diagram and photos with labels. The radio gear on the Second Try has for some time been my favorite AE briar patch.
Two queries that may or may not prove relevant:
1. In the diagram of the belly, shouldn’t the position of the Hooven or Bendix DF receiver be shown on the starboard side (not port), and shouldn’t it be a few feet aft of the WE 20B receiver position under the copilot’s seat, to allow for the space occupied by the bulkhead and the R1 tall fuel tank? This will be relevant to the question you asked, whether the long connecting cable that during the First Try ran from the sense antenna to the DF receiver, IF it was still in the plane during the Second Try, might have been repurposed to run from the transmitter antenna post to the WE 20B receiver under the copilot seat. That is, can we estimate the minimum length of that long connecting cable?
2. On the Second Try, what was the location of the cabin entry-point of the lead-in from the dorsal Vee antenna? Yes, the Hooven-era cabin photo you posted shows it clearly, where it no doubt still was for the First Try in March. But for the Second Try the dorsal Vee was lengthened and its forward mast moved forward, close enough to where the Hooven dorsal faired loop was located, that it makes me wonder if the lengthened dorsal Vee lead-in might have entered the cabin about where you note the Hooven dorsal antenna in the photo. But the question here is not so much that cabin entry point, I guess, but whether, once landed on Niku, they could have reached the dorsal Vee antenna from the open hatch over the pilot seat, in order to run a wire directly from the dorsal Vee in to the WE 20B receiver, through the open hatch?