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And here is a Sonora reproducer from one of my Nocturnes with a soft tone needle. I think you just need to find the right thumbscrew.

VanEpsFan1914 wrote:
A Sonora is a high-end phonograph and should be able to handle everything from soft to loud tone needles.

Some Sonoras are high-end, but certainly not all. Some models are just like any other off brand machines that use a locally manufactured cabinet with imported Swiss parts.
Even most of the Bombe style cabinets have pretty standard quality Paillard motors, tonearms and soundboxes.
The high-end models were usually fitted with Paillards gold plated motor with record counters, wooden tonearms and best soundbox.

But the soundboxes are pretty standard to a few types and all that I have can handle all needles.

Yeah, I've never seen any Paillard soundbox that couldn't take even a soft tone needle.
The picture posted by the OP almost looks as if the top of the thumbscrew has been JB Welded to the threaded part. It's hard to tell from the photo, but perhaps some of that lump could be scraped away so it could be screwed further in?