We don't really go by flat out # of gear options.
we usually just call it
1st-5th
1st-5th in 4hi (rear box in hi, crawl box in high (where it usually is for regular driving)
1st-5th in 4low (rear box in low, crawl box in high)
1st-5th in 4low low (rear box and crawl box in low)
1st-5th in 4low hi (rear box in high, crawl box in low)
And then of course you've got your reverse gears in 2wd, 4hi, 4low, 4lowlow, and 4lowhi
I've never heard anyone say "I'm in 13th gear," or "I'm in 25th gear" or something like that.
When I'm wheeling, I'll typically run in 4low, using whatever gear to get the speed I want (up to a certain point obviously) and when I need the crawling ability, I'll drop the crawl box from high to low, and then use those options, situation appropriate. I rarely shift the rear t-case when wheeling, I just leave it in low, and do the adjustments using the crawl box and tranny.