honestly, there are issues with newer derailleur cables.

With today's technology, they are both thinner, stronger and less resistance.

The problem with that, is our vintage stuff was designed to take thicker cables with less "slick"

I go to the local co-op and grab from the bin. sometimes its $1, sometimes they say, "get outta here"

Bring a lever with you, but most cables come with two ends and you cut off the wrong one for your bike.