A decent clutch refurb place should be able to install a new friction surface ( if you can find one who will be bothered )

If you machine some off it, you can restore clamping pressure by machining a corresponding amount off where the cover bolts onto the flywheel. It'll just mean the flywheel now has a slightly raised friction surface.

Before doing any work though you should have the cover tested to see at what installed height it offers the most clamping pressure and then aim for that