I decided to watch a 3D movie on TMT 6 before I made any changes at all to JRiver and the loopback setup. The movie played flawlessly, and changing chapters etc. didn't cause any stuttering like JRiver does (although it pauses for much more time in between which is ok for me). The 3D was perfect and the audio locked right into my outputs and the experience was basically as effortless and easy as I could expect.
Now after reading your entire thread, the fact that I use ISO's for all my movies has me concerned with the integration. I have no intentions of changing from ISO's. So what I am finding is that TMT 6 can output to Dirac Live's processor, and then Dirac Live CAN output to my ASIO drivers. So really, this is another work around for me.
I am going to try the integration for test purposes and see which one I like more. Right now I am annoyed that TMT 6 has no IPad remote (but has a Driod remote). So currently I have no way to change things without a mouse and keyboard at my side.