That's an interesting idea. A friend has a similar design of EBB on a tandem, the difference is the indents were pre drilled and the set screw pointed to fit in them, I don't know how they're lined up, maybe it has some external markings. Or maybe they do what I did and take one screw out to see where the previous marks are. It is possible to mess up an insert, but it's also easily avoided and if you do so there's no reason they wouldn't last indefinitely, as you're aware of it before use, I wouldn't bother with a spare.
