I think we are going to setup a few light events where we all can practice that. I have never done it before either.
For driver swaps don't do hot swap, while it kind of worked at SSCA an actual normal driver swap has turned out to be allot more reliable at many other endurance series like ILMS. In-fact there is hardly a disco with the normal driver swap now.
So your driving allong, team mate comes in your car to ride with you "<Name> Is now riding with you> You as the driver go to pit menu and scroll down to driver and select his name there, do the pitstop and then it will transfer over after 30 seconds or so depending on the mod.