i'm running skyjacker soft-ride 8" springs with cross-over also.
i run 3 diff size tires, 38" swamps, 42" swamps and 38" toyo m/t's, all on 16 incher rims. swamps are kick-a$$ off road, but HORRIBLE on the street. remember back in the day with bias tires how they would be square every morn? wait until ya got square 38's every morning, they will shake the fillings out of your teeth until they warm up and round out. second biggest prob i find wit my swamps is there is no siping.....lots of fun on wet roads, and if your running lockers...double your fun...
if your haul heavy loads wit your truck, i would not bother with rear lift springs. haulin' my camper flattened my rear springs in about 2 yrs, so i use 4" shackle flips wit a 3" block and airbags in the rear with GM H-D 9 leaf packs