Toasting the pecans is optional, but try it, it makes a difference.
I make my aluminum foil heat shield by taking a 1-foot square of foil, folding it twice to a quarter of the original size, and cutting out a round center. Then just lay the outer part on top.
I often let the pie get close to done and turn off the oven, leaving the pie inside with the door closed, so the pie can glide into cooling. This seems to prevent cracks.