Todd, mostly just giving you a hard time about the ER, technically you need to find the centroid of the area of the pad, and the distance from there to the center of the rotor is the ER, but, it's tons more work, and requires more info (like the the entire pad shape) and the answer will virtually always be within a couple of mm of your calculation
I guess I'm just too sarcastic for my own good . . . but only because its not really funny to anyone else, lol.
btw, on the Cf, it's a tough call, because it's really a mixed bag these days still. Really, the right way to do it, is for a factory pad to be near .38 like you said, because it makes dust and noise and brake roughness much less of a problem from a warranty standpoint, but a lot of vehicles don't end up that way . . . I know of one passenger vehicle line (not a Ford) that when we had thier factory pad tested for Cf to compare to one of ours, it came out closer to .55, so take that for whatever you will, lol.
