Take a look at the links and see if it gives you an idea of what to
do. If you have a vice you could trim the female part of the brass
fitting. Your local hardware, plumbing supply or big box store may
have the same items.
https://www.amazon.com/Anderson-Meta...emale/dp/B0070
TVKBM

No luck finding anything like this at Lowes. I don't have time to waste
running all over town trying to find one, so I just ordered the one from
Amazon. I also ordered a couple of different spout trim rings in case I end
up with a gap that needs filled.

The "Dresser" compression fitting I had thought of is HUGE. No way that was
going to fit inside the tub spout.

I also looked at several different spouts and all had exactly the same
offset as the spout I already have. So I might as well make the one I have
work.

Anthony