Yes this can be very confusing, however - this being Discoweb - you need to learn to weed out the "I've heards" and the "IMHOs". Listen to those that have run the set-ups that you are asking about and trust that their experience will steer you right. Now, in my experience with a DII w/ 4.11's F&R with dual TT's running 285/75 BFG M/Ts has been that it isn't too difficult to break stock CV's under the right circumstances. I went through 3 stock CV's (always the long side) prior to upgrading to CVU's, and each breakage occured while climbing uphill, turning with a tire wedged against either a V-notch, a rock, or a root, and with moderate throttle. The first two times happened with CDL unlocked and can be attributed to torque shock of the spinning tire grabbing traction. The last time I was CDL locked, I don't think the stock could handle the steering angle. Every time that I have broken a CV I have been able to get home with the CDL engaged. I haven't had trouble with the TT with them CV breakage, but on each occasion the breakage occured at either the bell or the star of the CV, not the diff side of the shaft - I am not sure how the TT would react to that, although I suspect that with the CDL engaged, that the otherside would still receive power, and thus get you home.
I hope this helps ease your confusion.