The capo should have a "dampening" rubber which touches the strings, so the "wear" will be on that.
You're not sliding it up and down too much, you shouldn't really slide it at all but we all do.
So based on that you should be able to more or less use anything you like. My only comment would be that most quality capos are metal so that they have the strength to depress the strings properly, so wood or acrylic would always be a second choice to me.
Also you will need to allow for the curve (if present) on the fretboard. That will be driven by the instrument you're making it for.
(Played guitar for the last 45 years in case anyone wonders)
Hope that helps.