I fixed the one I stripped on my old SR by using a cylindrical burr on a Dremel and cutting a new slot without cutting the tower down.
I'm well despised for this, but I disagree that the plugs should be automatically removed and the screws tweaked, for three reasons. First, mine are capped, and has stock jets, and it runs fine. That was verified to my satisfaction by a member who's been riding these since the 70s and has owned about six saying "There's nothing wrong with these carbs" with a gleam in his eye. His own most recent (Heritage mdl.) had a flat spot off idle that he fixed by going up one pilot. Second, the float has a lot more influence on the mix than the mix screw does. On the one that I have tweaked the screw on, it was hard to say the screw was doing anything at all to the rpm at idle. At best, there was a very wide plateau rather than a peak. Third, I doubt the average person, which includes a lot of first timers don't forget, could set them up better than the factory did. Not for a long time at least.