Crossover for vintage 16ohm horn paired with 4ohm woofer
I'm wanting to keep the speakers as they look to be in great shape.


I don't think they are. The paper and plastic of the membranes becomes brittle after 50 years. One boom and they are gone.

While you could use a passive crossover, this isn't state of the art any more (was it ever?) for horn tweeters – because of the impedance mismatch, you wouldn't get a decent volume out of them, and the capacitor makes it even worse. They should get their own amplifier with matching impedance.