I made up a bracket to mount the Swift radiator and installed it in the car.
I also put in the Suzuki fan & shroud (it fit!) and connected it to the Miata's wiring.
Popped the hoses on (with modifications to the upper hose, since it doesn't lead where it used to), and took it for a spin.
No leaks! And I confirmed the coolant fan goes on (and off) as expected when the hot engine is left idling. (That part of the test was painful.
)
Now that I know everything fits & works, I'm going to take it apart again, tidy up some details and re-install it. I'll get some pics this weekend.
It's a Franken-mod, but it works. It reminded me a tiny bit of
the way Cubans have keep their 1950's American cars running without access to proper replacement parts.