Do you have a dyno printout of your current power curve?

For the time being, if this tuner you go to knows half decent what his doing and isn't surrounded by 50 engines being rebuilt, chances are he knows what's going on. From what I've noticed, most good tuning shops are clean, organised and concentrate on tuning, not welding exhausts and building engines. But I am purely speculating here, everbody starts off somewhere and ends up transitioning at some point... so take that with a grain of salt.

Finding tuners who are experienced with the software will go along way before even tuning a car..