I redrilled my whole pack this time around based on Marv's experience, only I drill pressed them all at once (sorry Rene, thats too much work for me /forums/images/icons/laugh.gif ). I would reccommend you drill all the leaves and not just the main. My last set didn't do so well after flipping the overload with only the main leaf drilled... was a hybrid pack too so that may have contributed to its fatigue. With the weight of the truck on the springs they should give you stock height, but this assumes the hanger is in the right spot. With the various ways people are getting flipped and relocated, there are going to be lots of varying results on lift height.
I'd definately like to see and contribute to 57" spring swap tech article.