It appears that X3 Producer numbers takes in a kind of odd way.  I just did a quick test (new project using new per project folder), recording 2 tracks simultaneously. 
 
1st take, track 1 = (project name), (track name), Rec (3) 
1st take, track 2 = (project name), (track name), Rec (4) 
 
2nd take, track 1 = (project name), (track name), Rec (9) 
2nd take, track 2 = (project name), (track name), Rec (10) 
 
3rd take, track 1 = (project name), (track name), Rec (13) 
3rd take, track 2 = (project name), (track name), Rec (14) 
 
4th take, track 1 = (project name), (track name), Rec (17) 
4th take, track 2 = (project name), (track name), Rec (18) 
 
With the exception of the 1st takes, the file numbers increase by 4.  It would be REALLY helpful if I could get these to name themselves sequentially, as I'm using Sonar to do some field audio for a Video shoot & I'd like the take numbers to match the camera's file numbering.  The camera labels its takes 1,2,3 etc.  Is there a way to get Sonar to do that?
 

Is the field recording going to be multi track or just stereo? 
 
I ask because if you only need 2 or 4 tracks, possibly Sonar is the wrong tool for the job. 
 
Example, Wave lab sequentially numbers tracks, you can even create a new number without stopping the recording.  Possibly the free versions of Wavosaur or Audacity will do the same? 
 
But even better is a Zoom or Tascam Handy recorder. Mine a  DR 40 will do 4 tracks, Some of the Zoom do even more and are made especially for video work.  All the video guys I work with have one or even 2 and use them as the main audio recorders on a shoot. 
 
 

good suggestion... but the shoot's tomorrow.  :-)  I normally record straight to the camera, but we're using a different camera tomorrow that doesn't handle audio well.
 
thanks,
 
greg