As mentioned previously, I've had to heal so far because of... unforeseen circumstances.
Here's a target dummy log: https://www.warcraftlogs.com/reports.../#type=summary
Two caveats:
1. I just came home and messed up a bit - could've fit another void torrent in and I didn't play the rest flawlessly either (still 127 seconds of void form according to the insanity weakaura though)
2. I believe I went out of combat during first dispersion and the log only shows the fight after that... shouldn't be a big issue though
Edit: Nevermind, I don't think the second point is true.
Edit 2: In case you're wondering, SWD before 2nd void torrent is purely for DPS purposes. You can easily get there without SWD.