I'm recording piano solos ad need advice

If it's the same midi track... there's no benefit to doing it that way. 

the 3 tracks will be louder due to the cumulative nature of the audio.... but you will not have any meaningful advantage.

Simply bounce it down the center. Then you can pan it right, center, left or any point you wish. 

Doing it that way simply gives you 3 tracks with the same exact audio data and that equates to MONO. Unless the piano output is a STEREO piano, and has different audio info in the 2 stereo tracks..... you will end up with mono no matter what you do.... assuming the same midi track powers the audio tracks. 

The better solution would be to have a different instrument..... maybe an acoustic guitar and pan it opposite of the piano....and keep them both at maybe 20% panned from center. Or a nice B3 organ sample/patch..... That puts a balancing instrument on the other side and gives you some degree of stereo separation in the sound stage. 

I have experimented doing what you describe, and I always came back to one track...centered.  I tried several different things to make that piano sound bigger and better.....  inverting phase..... off set the tracks with nudge..... reverbs on some..... 

nothing was as satisfying as a nice clean piano in the center where I could place it where it was needed.  
By all means experiment and try things.... that's how you learn and who knows... you might find something that works in a given song situation. 

Is the library not already comprised of stereo samples? Just record a stereo track. No need to make it any more complicated than that.

Unless of course you are trying to get the low end of the piano on the left, the center octave in the middle and the high octaves on the right. You could divide your midi into those keys below the C below middle C on one midi track sent to audio and panned left. The octave above and below middle C sent to audio and center panned and finally, the notes above C above middle C sent to audio and panned right. Then as you play arpeggios from low to high, the sound would seem to move across the stereo field. Some pianos, although stereo do not sweep across the sound stage they sit in one position, depending on the pan position.

That trick with other instruments sound usefull I keep that in mind, Im looking compose cello pieces hopefully soon.

haha evil haha ok thanks for the advice I leave it in stereo with one track. I don't want be evil haha
It just looks so lonely by it self haha. But do love the plug in noo point make things complicated just record and post some than up "finally" is my goal.

Here off topic question  yesterday when I recorded midi track the track was blue the notes blue. I could not see dang thing. Sonar x2 advertise the background of tracks black but my was blue. 
Now this might sound crazy is sonar essential tracks spose be this way?  
 

If you have a semi decent piano library, the ability to widen it should be built in to the plug already, no need to add more noise to the mix if you do not need to. Marcus, what you were proposing to do would work if you were mono micing a real piano and wanted to create a false stereo spread. With midi, that work has already been done for you. The cleaner you go, the better it will be all around.