Sorry, but what's the difference between slipping the clutch and feathering it?

 

No difference between slipping and feathering, just choice of words.

Track use should have ZERO problems with clutch and driveline issues that aren't self-induced. It's only for those events that dictate as fast a launch as possible (e.g. autocross and drag) that the problem may be seen. As others have noted, there's been an awful lot of launches done without failure so it's not like the drivetrain is made of glass but anyone doing these has to expect a failure at some time...