Some type of power sander is the easiest way,but if you use files..make sure your stock is well secured and easily seen at your bench.Make sure you keep your file flat and work it down slowly staying off the stock..I work them from the comb down to the heal and can make the toe as sharp as it should be.I use 3-4 wraps of blue painters tape around the stock.A bastard file works well enough for most Lymbsaver's or Pachmeyer's..but the Hi-Viz you might want a less course one to work it down close to the stock.Those have a tendency to tear easier. A small sanding block with various grits of paper is also needed for final finish and smoothing out the cut marks on the pad,and when getting close to the wood on the stock..I generally take it off to do the final fit with little bit of sanding on it. The main thing when filing it is to take your time..
Mac