Don't knock the bar tape. The LBS that sold me my Peugeot in '87 installed a Pletscher rack on it. They put a wrap of cotton rim tape around the seat stays before they clamped on the rack. They also added a metal spacer strip from the clamp nut to the brake bolt so the clamp wouldn't slide up and down the stays.

Last week when finally I removed the rack after 21 years of use, the cotton tape had become black and stiff. But the seat stays were intact. Good installation job!

So I used bar tape under the clamps when I installed a clamp-on bottle cage on a '74 Raleigh Gran Prix that I'm fixing up with my son. We picked a color to match the frame. Looks good (at least for now) and does the job. But I suppose rubber would last longer.