like Benny said, you can run 32's with just 2" up front ( I did trim the valence under the front bumper, very little though )....4" will get ya 33's easy....
if just goin up to 33's, then 4.10's would work if ya worried bout' fuel mileage/DD duties at all.... 4.56's would be better off-road.....
if you want "the best" rear locker...Detroit ( not a Tru-Track ) all the way....
as for the front, always better to have the front locked off-road, however for winter/ wet highway would be better to be open.....for the best, and if funds allow, get a selectable front; either ARB or a Eaton E-locker....
good luck with the truck....
l8r, John