If rock crawling isn't what you mainly do, then dual cases aren't really needed. What percentage of your wheeling is done in 4 Hi, and 4-Low? If mainly in 4-Hi, and you find 4-Low isn't low enough for your needs, you could go with a single gear driven case with 4.70 gears, and just the one adapter plate. The 4.7 gears will basically give you dual stock cases, which will help with controlling wheel speed for dry hill climbs and any of the larger rocks you are finding you have to hit at speed or stall out on on the trails you run. Of course, with the 4.7 single case, if/when you do use 4-Low now you are usually in 1st or 2nd gear, with the 4.7's you will likely use 4th-5th gear, unless needing to creep along.
One trick that can help, if you have it, is kicking on the A/C, it will put enough drag on the engine while increasing the engine speed, to help reduce stall while trying to creep along, not so much for climbing onto a rock or ledge, but with descending them.
