I have the same problem. everything is setup great for my car stereo but i can only use HQ output and not SQ output. SQ output has no backlag on my phone over 3g but QH has a lot of lag time and can only use it through wifi areas, which is great but would like to use SQ output for my car stereo like Neflix is able to do.
I'm in the exact same situation. Before Video Out was a supported feature, I used a tweak to mirror my phone to my car's screen, but now that Slingplayer has the video out feature, it over rides the other software and I can only use the HQ video out. SQ Video out would be a huge help - really not even sure why it would be limited to HQ mode only in the first place.
Have you figured out a work around to output SQ video?
Sling developers: please enable SQ video out mode!!! Please