At long last I finally got a chance to really use my silverpoint kit a got a few weeks ago.  And I've come to realize that silverpoint is awesome!!!  Yep thats right, amazing stuff.  Kind of strange actually.  You can't do much with it compared to your average pencil.  There isn't "darker" or "lighter" strokes.  Its all the same, just different variations of thickness, cross hatching and such.  Its actually really similar to drawing with a very fine dip pen.  I guess its just really fun drawing with actual silver : )