We wheel the same trails have have similar setups, with the exception of I'm still IFS and run 4.10 gears. For the most part I will tool around in single low on the access roads due to my axle gearing. When we hit the rocks, I'll see how it is going, if I want to go slower, put in the front case, if too slow then, shift up with the transmission. I do run around with just the front case in as well, but not too often as I don't want to blow the input on the rear case. Go with the speed you feel comfortable with and your suspension can handle. I have done full throttle assaults with the engine bouncing off the rev limiter and two tires off the ground before without issue to the cases. I tend to get mad at the IFS on the upper blacks and reds at Rausch and use the throttle.