I don't really think about packing that much. Usually I'd just take a really big pinch - more than what would fill the bowl, and twist it in in a spiralling motion, press the top down with thumb and rotate the pipe all the time, tucking the edges in. Gives a nice, tight cylinder in the middle, airpocket at the bottom, and loose pack at the sides all around - it's like turning your pipe into a cigar and the briar is your wrapper. Can't say that I ever re-light, but I'm pretty sure that more due to the care taken to get a nice even surface glowing when lighting the pipe.