Adjusting several track levels, audio and soft synth - how to ?

I have a piece in Sonar X2 that is around 20 tracks - some are audio tracks, and some are soft synth tracks.  I got the relative levels just as I want them.
 
In the soft synth tracks I have some automation of volume.  In the audio tracks I have adjusted volume by adjusting the volume slider.
 
Problem is, my finished track with all the levels balanced is peaking at around -15db, quite low I suppose.   Whats the easiest way to get all my tracks moved up in relatively equal volume?   The audio tracks I could group in console view and move relative volumes together - but the soft synth tracks would not work that way (they have automation using volume).  
 
I tried manually to adjust each track seperately, but its tricky to get all tracks manually raised by the same percentage manually.
 
Any ideas?
 

I disagree about using Offset Mode.  The overall level can easily be adjusted in the bus stage.
 
What are your tracks routed to?
 

Thanks Lynn, I'll take a look at Offset mode - never actually heard of that before !
 
Kev999 - in this case, I'm actually routing all tracks to a Master bus - which is set at 0.  

Now, knowing your routing, I agree with Kev.  Simple and elegant.

Thanks guys.   
 
Lynn - I tested the Offset mode, and I will definitely use that again on individual tracks where I have automation.   If I'm understanding right, if the track with automation has volume fader set at 0, and I use offset mode to raise it +2, then back in normal mode if the fader says 0, it will actually play +2?    But, when it come down to zero (actually INF) then it still will play zero, not zero + 2db ?
 
In this case, as I need to raise EVERY track by the same amount of volume, I think the pre-master bus is a good solution.  I route every track there (and the Pre-Master routed to the Master), and use the volume fader to raise the volume --- that means I can raise it my max 6db.  The gain also has up to 6db.  Does that mean I can then raise every track by maximum 12db?   Is there any difference between pushing the volume fader +6db over 0, than leaving volume fader at 0, and using the gain - is the effect the same whichever I use? 
 
 

Offset mode... nice! Thanks, Lynn...Boy, Sonar is deeeeep! Had no idea!  Wish my brain could keep all this stuff on tap...

Leave it as it is!!
 
-15dB is quite loud enough for a studio mix.
 
Your Mastering Engineer will love you.
 
My only caveat would be if this song is one of several songs for an album and the other songs are at roughly a similar but higher level, i might raise the lower one up a bit.