Wow, interesting... Lo makes it a bit easier to manage your wheel spin, and with the Rubicon, your crawl rate is much lower than a normal Jeep Lo range. I think tires made a difference on the big hill, larger diameter tires worked much better. Evidence the yellow Jeep after us didn't have lockers and didn't spin his tires.
I realized I never ended up using my lockers on the trails! I did the whole thing in 4-HI. After you left i was thinking about what i said and tried it in 4-LOW and that was on flat ground by the camp sites. Now i wish i tried the big hill in low.