[LAU] Ardour: auditioner output and click track

Hello all, Basically, what are the auditioner and click outputs in Ardour for ? I'm currently relying on a 'primary' track to give sync to the rest of the tracks inasmuch as it's recorded first and everything else gets recorded against it. Quite often it is an acoustic guitar track. Problem is with this approach is that if the guitar track has to be redone, then it's starting all over again, especially when there are solo guitar bits. The click output could maybe provide something like a base sync but I'm quite allergic to click sounds as I find them distracting, let alone finding the right rate. Maybe daydreaming, but is there some kind of responsive momentaneous switch that could be hit by the heel and whose output could trigger a non-obstrusive sound/sample of some sort, dedicated to its own track ? It is so easy to tap the heel while playing to keep the tempo: it's be nice if it could serve as input for click track of some sort. Anyways, what is the auditioner Ardour output for ? It is not shown in the track/bus list and there's no bus assigned to it. And, any suggestion for creative click track use (and Ardour click track output/assign of audio file for click ?), or how to redo a base track when everything depends on it, would be appreciated. Cheers.