I love the LRP system. easy to program, good setting range and not too big or bulky.
I think:
5.5 = 9 turn
6.5 = 11 turn
7.5 = 12 turn
13.5 = 27 turn (or more like a 25 turn)
I typically use a 7.5 in my 2wd and a 6.5 in my 4wd on a loose track. If traction is good I'll go to a 6.5 in 2wd and 5.5 in 4wd. I don't race trucks.