Is there any way to create lead-in time?
Is there a way in n-Track to set the metronome (or recording settings) so that you have a couple of “click” measures before recording starts?
Thanks in advance for any help.
This forum, as many have pointed out, is a huge part of what makes n-Track such a great alternative to the more expensive solutions out there. 
Just wait 2 measures worth and have some blank space at the beginning of each file. You will want this blank space for a lot of reasons other than the metronome. If you are slightly early or late, it will give you some wiggle room to work with rather than a wv where the first 1/2 second of sound is potentially chopped off. So hit record while listening to the metronome, count your measure or two lead in and start playing.