I'm doing a quick survey on this in terms of:
1) do you slave Sonar to SMPTE?
2) how stable is it in terms of warble and flutter when slaving?
3) does Sonar embed SMPTE to the wavs or how do you export audio for the editor?

OK,  I do not use Sonar to record audio for picture....but I do tons of work for TV/Films/Commercials and long gone are the days you have to sync to sympte two different devices to hold sync.  To make things easier you should have a on-camera "Slate"   https://en.wikipedia.org/wiki/Clapperboard
 
but it is easy to survive without that these days.  when you are sending audio to the editor you will have to help him out somehow...depending on your work method.  You can give him a "2" pop,  send him a Broadcast wav (they are time stamped)  or an OMF of the recorded material.  Make sure you and the editor are working in the same frame rate and you can insert a Sympte off-set in Sonar by going to Preferences>Clock. That will make your Broadcast wav or OMF automatically drop into the correct place on a timeline.  If your offset is wrong it still is a very easy one-time fix for the editor.
 
I work in post production, not the actual production.  What I do 99% of the time is have a offset of :00:59:50:00 and have the audio start at :01:00:00:00.  At :00:59:58:00 there is a "2" pop (one or 2 frames of a 1k test tone).  This gives a 10 second roll up.  The reasons for these are old school, some younger guys sneer at this because they want audio starting on frame 1,  but every once in a while it saves somebody a lot of trouble.
 
Once you set up a system and you are consistent every thing will work well.  Stay in close contact to the video editor.  As a music composer I always try to go and pay for lunch with the audio mixer and video editor.  Get to know them and be their friend.  you will have less technical problems and get a lot more work.
 
Good Luck!

Hi Jimbo, thanks for the input. On smaller and shorter shoots visual sync works great. However, I am currently working on an international reality show and it runs like this:
 
Audio capture from 13 lapel sets, 2 room mics and a wireless feed from the ENG crew comes to my Laptop and desk via a Dante card and some other gear (RME etc).
We record in Nuendo Live, which syncs from a Rosendahl MIF timecode generator.
Every morning we sync the Rosendahl to realworld time via an LTC App on my Android phone which outputs a SMPTE signal through the headphone jack to an RCA connector.
The SMPTE clock starts (running realworld time) and all 7 HD cameras, 2 mobile audio bags and 4 iPads (via a wifi network) get synced to the audio system and then disconnected to run in Trigger & Freewheel mode. It's called JamSync.
After a full day's filming, the files are gathered and dumped into an editing suite which reads the timecode and lines all the takes from all the cameras up with the recorded audio from Nuendo by reading the SMPTE from all the files. It's frame accurate and we don't have to move anything except for the odd 1 frame drift over 12 hours of shooting.
 
That's how the big productions do it, which is great, but I was wondering if Sonar is reliable for this job.

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Yikes!  That is a way bigger production than i have ever been involved with.  Beyond my pay grade.  you might want to run a dual system with Sonar being the secondary as a test.
 
I run into an issue when i record multiple tracks live on my laptop.  When my RAM fills up Sonar shuts down. So I usually get about 20 minutes of 8 tracks.  My laptop is old and slow and I'm not getting paid to do these recordings so I just work around that issue.  Perhaps I need to change a setting to record direct to disk.  That might be a bigger issue for you.
 
As far as warble and flutter I use to sync Sonar to Sympte with a MOTU audio card and never had issues.  But that was many years ago and the longest files would have been about 12 minutes at a time, the time until the next commercial break.   My files where midi heavy with one stereo track of on-camera audio and perhaps 4 mono tracks of live musicians.  not as large as your situation.