Its not hard to fix / improve , but not much advice can be given in a thread really , with out knowing how the truck is currently tuned its impossible to give a direction to go in , and on top of that not every truck takes the same changes , and not all injectors need the same changes .
log the condition (rpm, fuel rate, timing) where the smoke is a problem. lower pulsewidth, and bump timing up a little in those areas. That will be a good starting point.