If you can find them and can find one with low miles use 90s Campy brifters. Ones made for eight or nine speeds. They have lots of small clicks. I have used them with all sorts of derailleurs and many types of freewheel and cassette. It is almost like friction shifting with clicks. Works better if used with Campy cassettes matched to the shift levers. But you can get away with ridiculous stuff like shifting six speed freewheels with Simplex Prestige derailleurs from brifters. The shifting will not feel as precise as a matched system, it will get the gear you want and not slip.
The big virtue is you buy one obscure obsolete part and it works with anything. If attempting to assemble a 7 or 8 from parts and you have to go whole system that is just a lot of old parts. Of course Shimano parts are way more common in the graveyard than 90s Campy.